Like you, I have some injuries that make a clutch very difficult on a long drive. I do love the auto trans. It shifts much faster than I ever could, and it's just a joy to drive.
For a Windsor engine, I would choose the EAOD. 4 speeds are much better than three, for all the obvious reasons. As said above, the ECU generally controls the trans shift points. But there are a couple of aftermarket electronic controllers available.
If you're thinking about a Coyote engine, then use the 6 speed 6R80 transmission. It has a 4.13 first gear, and 2 OD gears. Now that you can buy the whole package from Ford, it a pretty simple installation.
Because of the light weight of the car, You'll need to install a higher stall speed converter. I put a 3,200-3,400 converter on my 6R80. It is a significant improvement over stock. But it could use a slightly higher stall, like 3,400-3,600'ish.
Don't forget to plan for trans cooling. You cannot use the front
oil cooler alone. You'll need more capacity than that.
My car has an
oil temp gauge. Since I don't race this car, I don't need it.
Oil temp will usually be pretty close to water temp. I moved the sender into the transmission line, so I now have a trans temp gauge.