Yeah, I think you guys are on it here. You've got to water by weight, not by time or looks or whatever, you need to know what the dry weight feels like when you pick it up and don't water until they get to that point.
In my younger years I was always told that weed likes to get good and bone dry before getting water again and I've tried to stick with that although at times I'm probably not as good with it as I used to be just because of my disability fucking with me, a lot of times I just have to do things the way I have to do them.
With that said, I definitely let them get dry but, sometimes there might be one or two that could wait and they just have to get it with the rest, that kind of shit.
It's a fine line though, you certainly don't want to let them get so dry that they start to wilt but, you want to get somewhat near to that point though.