Bjj gi question?

I wouldn't bother. If it's for a tournament, then you might be concerned, but you can also shrink it too much and it won't be legal. Some tournaments are very strict about how tight a gi can be. It will shrink on it's own. I wash my gi in cold/cold and hang dry, and it still shrunk. Yes, you can stretch it out to some extent, but not to it's original size. Go ahead and work with the loose gi, during practice, it can only help your technique. It will shrink. If you're really concerned from a competition point of view, make sure you understand the rules for how tight it can be so you don't over-shrink it. The more you wash it, the more it will shrink, so you could always buy a competition gi that you shrink or that fits tighter and only wear it to compete in.