I made one very similar to what you have started there. It's the third from the left in the picture. I can't remember the exact specs of it, but I can double check when I get home. From memory, it's something like.... 64" ntn, 64# @ 28", 1 5/8 or 1 3/4" wide. Mine also was only a tiny bit over 1" thick in the handle area, so I added a couple pieces of leather on the string side to fill it out some. I built it with a narrowed arrow pass and flares, and tried not to let it bend there, but it kinda does. Not as much as a bend through the handle bow, but it does bend a little and that's fine with me. I figured it might, that's why I used leather to build up the grip and not wood. I didn't want to risk the glue joint separating.
I made the belly 'mostly' flat on mine, although there's a slight radius to it, and the corners are well rounded.
Mine thumps the bow hand when I shoot it, but I shoot it really well. Back when I used to keep score at the bow club, I shot my highest score with old 'Wart'... by a considerable margin.
Vine maple seems pretty forgiving of the little knots and such, and I may have violated the outermost growth ring in several places when I sanded it, but it didn't seem to bother it. It reminds me of yew wood in a lot of ways. It clogs up the rasps some, so you'll be cleaning them often, but it's nice wood to work otherwise. Cabinet scrapers work lovely on it once you get to that point.
I didn't heat treat it, and don't believe I even had to make any heat corrections to it. I just worked it au-naturale.
