If you do decide to rent NiceHash power by the way it's probably better given to a smaller pool as you end up with a much bigger cut of the block reward.
does this mean your "luck" is higher with a smaller pool compared to stable "smaller" payouts from supernova for example?
hashing with 7 1080tis
From my point of view it doesn't make a difference. If you choose a smaller pool you will find less blocks due to the lower hashrate of the pool, but you will get a bigger share if a block is found, so in the end it evens out...