Congrats Grandpa!!! After seeing how happy my Dad was I'm thinking the only thing better than being a Dad is being Grandpa.
I tried a 24" leather backed Ipe for my daughter...kept me busy while she was healing. It ultimately failed. Got to 8" I think before it ripped a splinter from the back. Wife wouldn't let me toss it out and she cried when it broke LOL. From what I've seen on bending bows here I'd think a stick of osage would work