One more thing I hear that people use slushes pool a lot, I was wondering if that is a good pool to use? Thanks
I've used the pool in the past and it worked fine (back when blocks were only 70bil ;-;) But I now mine on CKpool. It's up to you, though- the S7's are still good machines, and quite a few people on here have hit blocks with them iirc.
One suggestion, though- choose a pool with a decent hashrate. Pools with lower hashrates do not hit blocks as often and pay will be slightly lower in most cases.