I would truthfully not recommend the 6 pool cause it is pretty much killing yourself if it fails because you can not catch up in economy :P
What's great in my low-level leagues is that the 10-pool puts my in a disadvantage but the pysiological factor of them wanted to counter my zerglings often gets countered by me going Mutalisks. Even if my Zerglings don't succeed and don't even survive I often win due to economical harassment, which I can then go into Roach + Hydralisk (and expand ofc) since I know I am safe. :>
