r12 is better on paper and maybe in AZ it is worth the trouble. The 80 series is one of the best to convert since all the components are also made in the r134a configuration from the factory also.
You won't need to remove the entire dash to reach the airbox. Glove box, supports, and center dash components if memory serves. Noting too difficult, just a bit tedious.
Had both my power seats stop sliding back and forth. I could hear the motors trying to turn. I took out the motors and the gears. I noticed I could not spin the gear bushing in the gear cover plates, it was seized up. The grease had become hard...
I usually drive on a gravel road or loose dirt and lock up the brakes so the ABS kicks on. I have the Autel MX808 and used that to bleed the ABS on my 2008 F350. Haven’t tried it on the LC.