With such big investment i would personally wait for next gen gpus
Mining isnt so profitable atm , and we are still in btc downtrend
equihash asics on the way, next gen gpus on the way, 1080ti still overpriced
Entering mining you need to think longterm now, 3 month roi is over
my 1080ti's still didnt roi , if btc hit 4-5k $ i will just shutdown my rigs and wait for better time to mine, i wont sell them,  0,17$ kwh here