Try Buy for Baby hun.
I love love love my GFs at night. Yes they are sized but worth it. I have 3.

I can't think of any OSFA side snapping pockets. SSs are usually sized.

I've never tried GKs so can't really help you there but I know others swear by them.

I also wouldn't be too quick to buy all of my nappies the one type. What fits your DD may be totally wrong on your next bub. At least if you have a few different types there's some to fall back on.

THere are lots of OSFA pockets out there too.