HMS Beagle, I like your post very much.
I have heard of sealing all mating surfaces screw it down but, not quit all the way. Wait till the caulking is cured, then tighten the screws. Sort of like forming your own gasket. But this sometimes requires a strong frame for even pressure or adding more screws.
I'm going to stay with the butyl tape because I've had great success, usually doubling it, even triple it in some places and on a warm day it'll squish into a good seal. This means having to add screws to a compartment door frame for 'pressure fit' if they don't already.
I like sealants on jack mounts for strength and to seal screws/ bolts.
If you don't seal bolts/screws/threads on a jack mount having only perimeter caulk, it'll will act like a funnel. That's the problem I had with my new camper. Screws were not sealed to fiberglass body and leaked everywhere.