Thanks! — yeah, that’s exactly the kind of work I’ve been doing. The holes in question were drilled, filled with titebond wood glue / fine sawdust mix, later filled with more glue, and then had toothpicks in them, etc. There seem to be some kind of nebulous voids down in there because I still couldn’t get a tight fit: everything seems to just push in deeper after it sets. But it’s tight enough to work now, and all sealed up with wax. I’ll just make sure not to leave it in a hot car. 🙂
Since the outside line of screws that go through the airway go through two layers, the first metal and the deeper layer wood, I considered switching to bolts and tapping threaded holes rather than bothering with the screws and the glue and all that. Didn’t end up doing that, but I think it would work since it’s the same metal stock that I tapped on the “spine”. Maybe on the next one.
Thanks for the resorcinol tip — I’ll look in to that for the future!