Machamp power up?
I have a team of machamp (x6) ranging from cp2403 - 2579 (level 30 - 35). The best iv ones are of 96% and all at L32.5 (cp 25xx). I got another L9 98% 15a/d14s machop.
I'm thinking to power the 96% ones to the last breakpoint for blissey gyms or evolve the 98% machop and power to L32.5.
Which option is better for gym purpose?
p.s.: Obviously I can just choose one but not both options. If matters, 3 * 96% machamp in which 1 * 15a and 2 * 13a
Answers
This is likely true (haven't checked it). But you'll also be fighting against a lot of Blisseys that aren't level 40, and don't have a 15 defense. So the exact breakpoint for that particular matchup isn't that important. What is important is to power up a set of Machamps to level 30, and then work them up slowly, as you can, to the highest level you feel is appropriate for them.
What's your goal? Taking down Blisschanlax in gyms? Two maxed out Machamps will do that just fine. 2 or 3 player Ttar raids? Then you want 6 strong Machamps. This all assumes they have Counter/Dynamic Punch. Any other moveset isn't terrible, but certainly isn't optimal.
"Which option is better for gym purpose?"
For gyms you only need one Machamp powered high for Blissey, and up to two more level 30+ Machamp and/or Hariyama for backup against other fighting-weak pokemon. You are already close to that with your existing Machamp.
If you are wanting to low-man Absol and eventually Tyranitar raids, that might be a good enough reason to evolve and power up the low level 98% Machop.
Another thing to consider, since it is a lot of candy and dust, maybe just save that Machop in case of an event exclusive move.