Can you define "the hickory has some runoff"? What is 'some'? Hickory can take a lot of abuse, but don't expect it to be a miracle wood. Silk can keep a splinter from lifting, but it won't help against excessive grain run off. I really need to see the grain in the hickory (but preferably also the osage) before I can give you any advice. Can you post a picture? I sincerely discourage anyone to order wood without seeing it first; we bowyers are exceptionally picky on the grain and we must be.
There's many factors involved. The bow is 68" NTN, which is somewhat short for a 30" draw. Add a potentially marginal belly grain, questionable backing, first time glue up, stiff handle and stiff tips...it all adds up. There's a lot of possible things that can go wrong. You could get away with one flaw, but if several elements are not up to the standard, the bow might not make it.