I would definitely go for the EVGA GeForce GTX 1080 Ti FTW3 GAMING.
HeroMember mentioned above that
dual 8-pin" cards like the AORUS 1080 ti line and the EVGA FTW are a NIGHTMARE to provide power to in a multi-GPU setup.He further said
8 + 6 cards like the EVGA SC and ASUS Turbo models are MUCH easier to deploy in quantity
My question, why are you recommending EVGA FTW3 line?
Just a personal preference. I like to go for the best quality to avoid potential problems somewhere down the line.
That said. I do not have first hand experience with that card. So maybe the hero member may be right.
Though i'm pretty sure you could run them with just the 8-pin, or worst case buy 8-pin splitters which would probably complicate things. But in the long run may be worth it if you get better quality.
EVGA SC and ASUS Turbo models are of good quality as well. So whatever you decide to do, you can't lose.
Like i said, just my preference.