I know this may run counter to what some say, but stringing them early will help eliminate the "under weight" problem. I will get my short string on one as early as I can. I want it floor tillered well so there are no weak spots, and I want the two limbs close to each other in weight. I then check it with the long string to make sure it's close. If so I string it with 0" brace height. Basically just a taught string with some pressure applied. I pull it a couple of inches and look at the tiller. Address the stiff areas and check it again. When it looks good, I check the weight. (just at a few inches). I'm typically very heavy at this point, but I know where I'm at. I'll then cinch it up a little tighter, maybe 1-2 inches and check it again. It's been my experience that the set comes from over stressing a limb in some way, either a hingey spot pulled to far, or simply drawing one too far too early. I don't do either of these things. Little steps an inch or two at a time. A lot of wood still comes off the belly at this point and if the limbs are even, any compressed wood ends up on the floor. I wont say you cant miss weight doing it this way, as some trouble spots can still rear their ugly head later, but it will greatly increase the likelihood of hitting what you are shooting for.
I would prefer that I could floor tiller, gauge it correctly, string it and it's near perfect, but I've missed far too many doing that, especially early on in my bow making. Truth is, I now can gauge it better at floor tiller and might not start at 0 inches. Might start at 3 or 4 inches and still be heavy when I brace it. I get them floor tillered evenly and get a string on it early.
Been following from the start. I like what you've done!