Yes, the Brits call it "over-stuffing", Paul, a term borrowed from upholstered furniture. Funny, when I first read of an armchair being described as "over-stuffed", back in my youth, I thought it was a derogatory term indicating the chair was too full of padding to be comfortable... :U
You are spot on with your suggestion it's more difficult to over-stuff than keep the woodwork flush with the insides! I'd like to let you think I just bash 'em out nonchalantly, but honesty compels me to admit it's one of the more difficult parts of the build. The fit has to be very close as even tiny gaps between metal & wood stand out like the proverbial dogs' bits. I'm getting better at it, it's really just a matter of accurate layout & working ultra-carefully to your lines, but with these darned curved sides, the stuffing won't fit 'til it fits. When you attempt a trial fit, the inside is obscured & you can't see where it needs a bit more pared away. The way I find them is by pressing the wood down carefully over where it needs to be, then looking for any scraped or burnished areas indicating the high spots. With a few earlier ones, I was too impatient & pared wood away from the wrong places & ended up having to start over! Making a mock-up from scrap before you start chopping up a chunk of valuable wood is a very good move & helps you to iron out the potential pitfalls.
I've followed the "challenge" builds pretty closely & have noticed two challengers have overstuffed their front buns, but not the rear wood. The front bun is usually a bit easier to do (well it's smaller, so less wood to pare :; ) so it's a good place to start if you want to try the technique. Both the buns I've noticed are very neatly done, so Brownie points will be accordingly awarded, no doubt.
BTW, I don't recall seeing other than smoother-sized planes over-stuffed on oldies, all of the old panel planes & jointers I've seen were "understuffed", if that's a term. There may well be modern makers who've done it, & I dips me lid to 'em, cos all that extra joint along the sides would add to the difficulty of getting the fit required!
On the subject of future pain - I'm not sure if & when I will get over my current shoulder problems, I can't even get a satisfactory diagnosis, let alone a suggested cure, so if there are any more planes coming out of my shed in the short to medium-long term, they will most likely be very small ones! Perhaps I should bite the bullet & invest in a good linisher (& spend the next year learning how to use without doing more damage than good... :roll: )
Cheers,