I tow with a 7.3L CCLB DRW. I regeared from 3.73 to 4.10’s but the 4r100 is a 4 speed transmission, I can’t imagine what a 8 or 10 speed transmission would be like it. I’ve towed over 15K with it in the heart of the Rockies without issues.
If I wasn’t so cheap
and was going to buy a new TV, it absolutely would be a CCLB DUALLY and geared as low as possible period. My truck is a tow rig and I want a long wheel base and a stable rear end i.e Dually.
Regarding driving it empty, I pull through spots and take both parking spots so I can pull out of the parking spot. Only one time I had someone make a comment about it in a parking lot that was 1/3 full...apparently getting out of the truck and walking up to them to discuss the issue further also solved the issue.
I would not worry about parking anywhere even a city street, it’s a licensed vehicle park where you want. I carry several orange cones just in case I get a flat tire on a busy road or interstate, I also use it to mark the rear corner of the truck if I park on the street.
I’m like you, overbuilt and overkill are the only way to do something. The new transmissions with 6, 8 and 10 speeds are absolute beasts then add the electronic monitoring and the built in temperature gauges you have nothing to worry about but personally I’d get the lowest gears I could. I think your hardest decision will be color.