That should work Stan, pretty similar to bedding compound, not runny and will do the job. I like inletting wood better than a plastic type of filler, so if fitting is required after build up, I prefer wood.
Mr. Potter once shared with me that there are wrong ways to do a job, but quite often more than one good way to complete a repair exists. I think your idea has merit. I use sawdust combined with wood glue or CA myself. Certainly worth a trail run, even if just done a piece of scrap to get a feel for it.
Steve