You sound like you are on the right track. Most of the kids bows I have done are board bows, with one osage kids bow. If you make it 52-54" ttt and tiller it out to 24" she will have plenty to grow into. Check weights at different draws but if you end at 25-30# at the 24" draw she should be good to go. I would not worry about inducing much reflex in this bow. A little string follow wont hurt a bit and will make for a softer shooting bow, less hand shock (i believe). Keep it simple and elegant and she will love it. Easier to get a shooting bow as well.