I just finished the bow yesterday... sanded out, finish applied, and leather grip stitched on. When it's dry, I'll take some more pics. Finish on ipe takes forever to dry, so it'll be a day or two before it's dry.
If you have enough thickness at the riser, and you tiller the bow not to bend through the handle, it won't pop off. You can't tiller out the bow and then attach the riser. It will pop off.
Because ipe grows year round, it's often difficult to determine grain orientation. I try to avoid big knots that I can see in the wood from the beginning, but I don't worry much about small pin knots or small grain swirls.