Hi bubbles, Thanks for the welcome!
You're not crazy, that is a splice in the middle... I had a terrible time finding something with a straight grain that long... I figured that, as my handle is non-bending, it couldn't hurt to make a two-piece backing... it's maple almost 1/4" thick.
Thanks for the tool suggestions, I have a ferrier's rasp and might try that, but as I mean to keep the belly flat, I think my best bet is the belt sander. (The belly is oak, sands really easy...)
Thanks,
John