Soft backings like the FG tape, silk, linen, heavy paper, etc will help prevent splinters from lifting but will not prevent a bow from breaking. The grain along the back is critical but the grain along the sides is just as critical and along the sides is one place many folks don't consider. Finding a board that has appropriate grain, back and sides is virtually impossible when looking at the wood supply at a big box store and even your standard lumber company. Places that sell quarter sawn lumber like specialty lumber suppliers is a better option.
Your best bet for a successful bow would be a stave or billets joined at the handle, a piece of wood that will allow you to locate and chase a good clean back for your bow.
You beat me to it, Willie.
