Howdy John.......
I think you're "getting it" or "seeing the light" here! A woodturner is best off to avoid needing to re-turn, or re-sand the side of a bowl, once it's re-chucked in the Mega Jumbo Jaws......that's where all the trouble starts, and you could very well end up losing the bowl altogether, or having a major "fix-it" to do!
Any surface that's intended to be finished on one chucking, is usually asking for a disaster if you mess with it on a subsequent chucking. If you have to lose a tiny bit of "real estate" (as you call it), well, so be it......much better than gambling on the outcome.
I started out on a Nova chuck with the Cole jaws.....and have graduated to the Stronghold chuck with Mega Jumbo Jaws about 15yrs ago. After about a decade of non-use, I ended up selling the Nova chuck and Cole jaws several years ago......(Nothing wrong with the Nova chuck, or the Cole jaws, it's just that the Stronghold and MJ Jaws do exactly the same thing, plus have a larger capacity.) As far as I'm concerned, these big jaws with the rubber bumpers are a fantastic invention that I couldn't live without!
You will find most bowls have a degree of warp, after it's reverse chucked. This will become more obvious when you see that very few bowls will set perfectly flat on the Jumbo Jaws, when viewed from the side as you are chucking up.
One thing to remember: The smaller the diameter your foot is, the less any warping will have any effect on it.
Even if you do have some warping, it's very easy to true the very bottom up while it's on the Jumbo Jaws.......just use a very fine, and delicate scraping cut, and/or a 2" sanding disc, also held very delicately against the base portion of the foot that contacts the surface the finished bowl rests on. (At this point, you should NEVER have to re-do anything on the sides of the bowl.)
John, I checked out your web site......Most of the bowls I saw have, or appear to have fairly thick sides. Secondary warping of pre-seasoned bowls should be less with those than a thinner wall would have......but, then again, each and every piece of wood seems to have it's own individuality, and it's hard to second-guess what they all will do without having a crystal ball!
(Every time I attempt to make hard-fast rules about something involving woodturning......I usually end up eating crow!)
You have a very nice sense of design.......simple and clean! I like your style.
otis of cologne