Double Weakness Defenders (Gary, Dragonite, Rhydon, Tyrantir)

I rarely grab Electric or Ice either.

I fight the real dragon with dragon (it helps now I have two useful ones instead of just one) and I fight the fake dragon with the panda or t-rex or golem. The ice and electric attackers are useless whenever you stray away from their 'optimal matchups', where as you can use the panda/trex/golem for quite a lot of stuff.

My attacking lineup is:
1. Dragonite DB/DC
2. Dragonite DT/H
3. Trex B/C
4. Snorlax Lick/HB
5. Vaporeon WG/AT or HP
6. Another Vaporeon WG/HP or Exeggutor Con/Solar or Golem (Number 6 is usually a free parameter, I adjust it to meet gym needs, whereas the other 5 are fixed, unless there is no Rhydon/Tyranitar in which I may choose the ice/electric to replace number 5)

Ok so yeah I actually made a post very similar to this a while back and in it I explained that the 2x weakness mons are fine by them selves some even necessary in a gym such as a DT Dragonite but I also said that if there is to many in a gym it becomes worth it to use a pokemon who can take advantage of their 2x weakness. I also pointed out hiw since Blissey and Snorlax are the main threats that people will for the most part allways have a SoB eggs, a HP vape, and a Machamp/Heracross so that makes Rhydon and Tyranitar well under avegrage but because so many people sware by the FS/OH Flareons and Charizards it makes a SE Rhydon beneficial but because of Tyranitar always being at the top of gyms he well still is useless. And as you pointed out Gyarados is by far the best 2x weakness defender because if there are 3 in a gym most of the time I still wont pick a Jolteon it is just not worth it to bring a Jolteon in this Rhydon infested Meta.

Sometimes if there is a Gary and Dragonite back to back or a few in a row then I bring a Jolteon. I personally really like attacking with a Jolteon and use him a fair bit vs Dragonites as I won't usually bring an Ice mon to a fight.

But it seems most gyms here have Garys and Dragonites so then its worth it for bringing a Jolteon as it can take out a couple of both as long as I don't miss a dodge.

I use the appropriate attacker to match for every defender, unless the gym has more than 7 Pokemon.
My main attackers are
2x Gyarados DT/OR for Dragonites
2x Gyarados DT/HP for Blissey
1x Dragonite DB/DC for Snorlax/SW Dragonites
1x Dragonite SW/OR for non-DG Blissey
4x Vaporeon WG/HP for Rhydon/Tyranitar
4x Jolteon TS/TB for Gyarados
1x Flareon FS/OH for Exeggutor/DG Blissey
1x Exeggutor C/SoB for Blissey
2x Exeggutor ZH/SoB for Blissey
2x Exeggutor ES/SoB for Blissey
2x Rhydon MS/EQ for Jolteon*/BS/HB Snorlax
2x Snorlax L/HB for DC Dragonites/Crunch Gyarados (no SE text, less missed dodges)
*People put Jolteon here despite the low CP because gyms here flip fast and rarely get past level 7, most people just collect 10 coins daily and slot random stuff.
Attackers that I still don't have:
Machamp with double fighting moves
Tyranitar with Bite
Rhydon with MS/SE
Dragonite with DT/OR

Gyms often are not level10.
A x1.56 weak pokemon in a Lower level gym makes it significantly Weaker.
Level 10 gyms usually are full of Dragonite (which is ok for Defense, Imo), Gyarados & Rhydon.
Gyarados and Rhydon are meh in Defense especially if there are multiple of them in Gym, And usually There really Are multiple of them.
That's my opinion.

I have a 98% Gyarados with DT/HP and never powered up (I have another 96% B/HP level31 nice attacker, but I prefer Vaporeon!).
I have a 91% MS/SE Rhydon never pushed over level 30.

IPreferVaporeon

^EvenAsDefender

DonphanIsBetter

Tyranitar is doubly weak to Fighting, not Water. If I took on Tyranitar protected by Blissey/Snorlax, Machamp would certainly be in my lineup.

Double Weakness just for prestige!

Otherwise I just CP the hell out of them!

I have only powered up two Rhydons with M/E and M/S--neither maxed--and I rarely place them because they share so many weaknesses with the common high CP defenders and I don't want them right next to something that shares a weakness.

If there is any Blissey in a gym, then players--if they even have a strong fighting type powered up--will probably be dedicating their fighter to take out Blissey. As long as Tyranitar is not placed directly after a Blissey or Snorlax, I think the double-fighting weakness is probably okay. I save my B/St Tyranitar for attacking though, and I'm not going to waste any more candy on my it/F Tyranitar.

The double weaknesses of Dragonite and Gyarados are not shared with so many other pokemon like the others. Rhydon has a single weakness to Ice, but water and grass are better choices. Vaporeon is weak to electric, but grass is a little better choice because of resistance to water. Two back-to-back Dragonites or back-to-back Gyarados is a problem, but that is true of any pokemon.

I agree there is a certain threshold before it is worthwhile to bring an ice or electric attacker. One, probably not. Two, maybe. Three, definitely. I have two Gyarados with D/O and D/C, and try to only place in a gym if there are no other Gyarados in it. Bonus points if I can split the CP of two back to back Rhydons. ;-)

I usually bring a Jolteon or a Lapras to attack a gym...If I am trying to clear all 10, I usually just stick to Vaps since they are more tanky or if my Blissey is not stuck in a gym, I bring her too to clean up. It is cool to not faint on a dodge bug Hydropump from Gyarados.

Unfortunately, I don't have an attacking Dragonite or Gyarados (or any Gyarados) so my options are pretty limited...

I usually bring 2 Lapras, 2 Vaps, Eggs, and maybe 1 Jolteon if there are a few Gyarados...but since I get dodge bugged, I think I just attack Gary with Vaps...2 Vaps can probably clear out 5 or 6 Rhydons alone. 2 Lapras can do 3 Dragonites. Eggs can do Blissey if there aren't that many and if there are more than 1, then I probably won't get an all clear probably.

Usually, it's probably not even worth fighting the Blisseys for the all clear 1k bonus since it will double your attack time (70 secs probably to clear one) vs. taking out any Gary in 15-20 seconds...Rhydons melt too against Solar Beams.

Your playing​ style seems a bit strange to me. At least is completely different to mine. I always go for the SE match up. If ​there's Gyarados or dragonite I go with jolteon and cloyster. I can't stand a long, boring fight when I know that there are better choices. It is possible that I got used to optimise my line up because it took me ages to get an attacker dragonite (and still not the best moves...it is DB/DP). I only use dragonite to muscle up when there are 3+ Blissey. But most cases I still prefer going with machamp or my army of primeape if there are a combination of Blissey + snorlax. Dragonite would be only used to finish off.

Its a very general question and the answer depends on what each pokemon each player has available. I have 4 Lapras and none of them are double ice moves. 2 are Frost Breath + Dragon Pulse. 1 is Water Gun + Ice Beam and the other is Frost Breath + Hyrdro Pump. I have a few Jolteons that I don't use, because regardless of CP, if you time a dodge wrong, you're finished. Basically outside of the matchups OP has mentioned, Electric & Ice Pokemon border on the brink of useless. Also I almost never see Tyranitar in gyms. The one time I saw one, I quickly defeated him with my Water Gun/Hydro Pump Vaporeon. I see lots of Vaporeon, Snorlax, Dragonites, Rhydons, Gyarados and Blissey in my local gyms . For a tower of 10 featuring the common defenders I see, I power straight through. I'll use 4 Dragonites. DB/DC DT/O DT/Hurricane and SW/Hurricane. The final 2 spots rotate between ES/Solar Beam Exxegutor, Gyarados with either B/HP or DT/HP, Espeon with Confusion/Future Sight or Golem with Rock Throw/Stone Edge.

Forget about placing that one specialty mon to exploit a double weakness for attacking enemy gyms. That's overrated. Use multiple powerful generalists to go through level 10 gyms for efficiency. Only time I concentrate on exploiting double weakness is for prestiging.