95% complete
el5Dart,
I've found out over the years that the best AC folks you can trust and even work with, looking over their shoulder, are ones that do it out of their home garage, they have the skill, tools, etc and do it on the side for their friends, neighbors, others. You need to start asking around your area or at some of these car clubs and shows, about someone like that. First, they will have to determine if your AC system is "sealed", most likely by asking you if you've replaced any components, how old your compressor is, new evaporator, condesnor, drier, lines, etc, seals and hoses get old and start leaking. Then they can connect up a vacuum pump and determine if it's sealed and will hold a vacuum without leak down. I'm not up on the latest but all we did on my D100 Ram is all of that, then installed the proper R134 fittings to the hi and low ports so that the R134 gauges will connect. Charged my existing R12 system up with R134, worked great for many years. I'm in the process of restoring my D100 now but plan to do the same process when it comes time to gas up the AC. Others may have some suggestions to add here. Good luck!