Doubles? You slay me! My knees would crumble. Nothing like hurting myself even more.
Four dives/two charters in one day was only because I really, really, really wanted to see a particular wreck (Wells Burt). What made it worse is that the Wells Burt is off Evanston, first suburb north of Chicago, which is 25 miles from the Hammond Marina. AM charter is at 7 am, and we didn't get back to the marina after the PM charter until 7pm. Long day! I've done two charters in one day last year, but they were not far from the marina.
I think you should sue the charter operators for not having a lift. Clearly they are the cause of your woes.
While I agree that warm weather is detestable I seem to recall that where you live isn’t exactly cold. You could try the northern Red Sea wrecks early in the year. You need to take a jumper and a 5mm. A drysuit is ok but a hassle for the travel. You need to walk about 20 ft with your kit on to dive, you can do four (maybe five) dives a day so can decide to skip two for longer naps and still have a worth while trip. A hoard of little Egyptians will do all the heavy lifting.
Or you could come to Scotland now, 10 to 12C water, 12 to 24C air but every boat has a lift. Scapa skippers have cylinders and lead, you would need to bring the rest. Of course you’d have the piss ripped out of you if you dived sidemount.