There are quite a few abilities I'd like to back.
CompoundEyes: CAP will want some strong moves, possible some of which are inaccurate. Reliably connecting with moves can help to maintain pressure on your opponent, and missing a crucial Air Slash(for example) will lose a LOT of momentum. THis can also help some of CAP's possible supporting moves, like Toxic, which can help ro ruin sweeps of the opponent, giving you a chance to gain momentum. CAP1 would really appreciate 100 acc Air Slash, 91 acc Hurricane and so on, and this will help us to gather momentum easily.
Unaware: CAP will have to stop the sweeps of several Pokemon like Reuniclus, Excadrill etc. Unaware helps it do it by not having to worry about stat boosts, so it can focus on beating them. It allows CAP a variety of switch ins, and combined with possible access to Roost, allows it to shut down close to any sweep and turns the flow of momentum on its head.
Mold Breaker: This has less impact on its STABs, and more on its coverage moves. There are several Pokemon who utilize abilities like Levitate/Volt Absorb etc. to make free entrances, and the ability to hit them on their switch in will definitely help gain momentum.
If you've noticed, all 3 of these abilities gain momentum by focusing on a component of a Pokemon. I feel this is how we should take this Pokemon, because if we attempt to make it gain momentum against Pokemon as a whole, we will end up with another Krilowatt.