Maxing out
I'm looking to max out one Metagross (meteor mash) and a Mewtwo (shadow ball). Stardust and candy isn't an issue, but not sure which to invest in.
Metagross
Lvl 30 14/15/14 96%
Lvl 30 15/14/13 93%
Mewtwo
Lvl 30 15/11/14 89%
Lvl 30 13/15/14 93%
Answers
One attack = 2 defense or stamina in my books.
For Metagross you're 1 extra attack for 1 def and 1 HP: so they're even. I'd check if the extra HP results in an extra HP at 40, if not pick the 15 attack. Otherwise it shouldn't matter.
For Mewtwo: 2 attack for 4 HP/def. Again even. In this case I'd suggest the 15 attack just in case a break point can get hit. Mewtwo is a cannon anyways.
Isn't it a little late to be maxing out a Mewtwo? You probably should have done that at the beginning of Mewtwo month.
Further, with the Metagross, don't max it out until you have a use for it. Of course, neutral gym sweeper is a perfectly fine use for either or both of these pokemon.
That said, assuming your IVs are a/d/s, I'd lean towards overall top CP in both cases. For the tiny number of cases that you'll not reach the last breakpoint with a 14 or 13 attack (very tiny if your Mewtwo has Psycho Cut), you'll get a small bump in Defense and Stamina you can use in EVERY battle. That small bump will occasionally save you a potion, and less occasionally be the difference between being KO'd and not KO'd.
They're all good, and you can't make a wrong decision here, but I think the higher CP ones are slightly more optimal.
"you'll get a small bump in Defense and Stamina you can use in EVERY battle"
This is untrue. Just like attack IV only makes a difference if you reach a breakpoint, denfense IV only makes a difference if you reach a defensive breakpoint (and a combination of defense and stamina for a bulkpoint). As for stamina IV, it only makes a difference if you reach a number of HP which allow you to sustain one more hit, which again is not the case every time.
The higher the difference in IVs, the most likely it will change something, whatever the stat. Also, the weaker the base stat of the pokémon is, the higher impact a single point of IV in the same stat will have.
So... it depends :D You can consider than in a DPS centric meta, offense and breakpoints matter more than survival and therefore attack is the only relevant metric. Or you can consider than Mewtwo benefits more from a defense IV point than from an attack IV point considering it's unbalanced base stats. Neither points are wrong, it depends on your priorities, playstyle and resources (especially healing items).
The highest IV on each case. If you're maxing out one point difference of attack IV (or def, hp) doesn't go anywhere (in most situations, there may be a few exceptions). The only reason behind selecting lower total IV to favour attack IV is precisely not to max out (i.e., reach the highest breakpoint at the lowest possible level).
I don't think you can go wrong here, as other commenters have mentioned. Metagross seems to be here to stay, and in the matchups where it deals SE damage, it will always be a top (or the top) option. I actually maxed out three Metagross yesterday, so my recommendation would be to do both rather than either or.
Regarding the Mewtwos, I think you're fine with either. I'd probably go with the one with the highest max CP since the differences between them are mostly aesthetic anyway.
