Marquero,
Your bow looks really good. I don't do board bows and I don't cut shelves in so I shouldn't comment about those areas, but if George is right about the runoff then I wouldn't waste any more time on it unless someone with experience with runoff can give good advice on how to make it more than safe.
I know that rawhide is a good back protector but I dont' know if it actually strengthens the back, such that you would have to remove more belly wood, in the end, in order to get back to your weight. I might try the rawhide just to see. Personally, if I wanted to really save the bow then I would sinew it....but that's because I also don't back with wood.
If, in the end, you decide to rawhide it and can't find some good rawhide then PM me with your address and I'll send you some. Give me the exact dimensions of your bow.