Winrate is not very important, because it's affected by variance and 100k samplesize doesn't have to represent it very well.
I wait to get suitable BR and then try new limit, move up and down few times. It's good strategy imo, because as soon as I realize there're better players on the new limit, I'm happy I can play those fish on lower one and immediately increase my winrate ♦
It can sound silly, but i did it between 2/4 and 3/6 quite successfuly (after downswing) and it works now too. Difference between 5/T and 3/6 is more significant though, but it gives me a lot of confidence and that pays off so far.
It depends on you, so it's not easy to tell you DO THAT / DON'T DO THAT. If you're rolled for 3/6, give it a try (with less tables ofc) - you can always move down.
edit: we used to play on Party at micro limits together, right? Mr.Cakara was your nick
edit2: I never really beat 0.5/1 and moved up just because of bonuses