Howdy Kenth,
Since you have a very short stave (for you drew length) and you have a pretty nasty knot in the handle area, I think you should consider making a primitive, bend-through-the-handle type of bow. That way, you'll be using all of your length as bending wood, and the handle area will be about 3/4" thick with rounded edges.
You might still have some of that knot remaining in your handle area. So, you may need to thin it more and then glue in a 1/4" or so, piece onto the belly side of the handle, as you inquired about. I think you could get away with that. Maybe you'd have to use a few thin laminations to build up that 1/4" thickness. I'd then wrap that area with rawhide or sinew or some strong cordage. I'm not sure what type of glue to use.
Or, rather than going for broke, maybe you should build this stave as a really nice 40# bow for lady friend or for a young person.
Good Luck,
Canoe