Update: It took a while to decide what to do with the leftover parts after completing the 924-sized alternate build, and I chose this excellent retro WWII style MOC with free instructions as a starting point:
https://rebrickable.com/mocs/MOC-124992/piotrusb/twin-engine-space-scamper-alternative-with-galaxy-cruiser-from-10497-galaxy-explorer/#details
I modified it quite a bit (with non 10497 parts) for a thinner, simpler and sleeker overall shape, a nicer cockpit, better seating position, a vertical thruster like the bigger ships, and I added detachable armament pods under the wings, allowing this little fighter to carry the large cannons of the 928 and 924.
I also made it dockable on the 928, to hitch a piggyback ride to far destinations (think Dornier and Short WWII piggybacked seaplanes), with 2 simple 1x1 round studs that attach it easily to the nose of the bigger ship, and in such a way that the combo is still mildly swooshable.