The 5 active members is all you need if the feedback they give is good.
Granted, it might depend on the sort of feedback you are looking for as well.
As such, make it easy to give feedback, by stating what you want specifically (ie, grammar, punctuation, pacing, etc), otherwise you'll end up with more general advice (in my opinion). There really is a lot to writing, and trying to go in depth for all of it will take forever without generalising a lot.
Anyway, still put it up since if the story is good you might get a commendation, totally worth it right?