I saw how the guy from Snowdonia Campers on YouTube took his doors off - wind down the window, it balances on your hand if you open the door, stand behind it and put your arm through the window and hold it just where the bottom edge curves down. With a 6mm hex drive socket bit, extension and ratchet spanner, all is ready.. Helps to be fairly ambidextrous as on one side or the other you will be using the wrong hand. Dont forget to tap out the door stay pin first. Been doing it quite often to get at the door pillar while I fix the front of my bus. When you put it back you will realise why the screws are pointed, as it helps lift the movable plate in the hinge attachment to the door pillar. The door pillar metal is surprisingly thin.
These days it is almost getting to the point where you put 12 volts unswitched on a single wire, and have an ESP32 or more recent WiFi module doing audio for the speaker via an amp and operating central locking .
Dave Rustoration - 1979 Bay rebuild If you look at this chaps resto pics, there's lots of details for wires into cab doors and sliding door. He told me the door fittings he used were these https://www.ebay.co.uk/itm/Central-...-Rubber-Boot-Protector-Brand-New/221929935068
Done that literally hundreds of times but it's still heavy and if you have nice paint getting the first screw in while holding the door, watching both hinges for alignment while it skims 1/2" from the edge of the front panel takes some practice. 100x later I wouldn't hesitate, I have the balance, I know it will try and seesaw on my hand and all that. Being built up makes all the difference, a bare door is lighter obviously but will balance more easily. Also this technique does require longish arms.
Some useful details of getting the motor on the sliding door lock too – I hadn’t thought of mounting the motor at an angle but it makes perfect sense.