thanks to anyone reading yet another AC thread. This is my first on this very confusing issue, especially to us less mechanically-inclined.

My 1981 300TD, with a good R4 compressor, has been filled TWICE this summer with freeze12 and can of oil from the dealer that sold it to me. After this expense and some extra dye, I finally tracked down what appears to be the only leak = lines right into the compressor.
Went to find those larger metal/rubber o-rings and several parts stores sold me the wrong parts until I took one into NAPA to compare.
More fun adventures; find that the three 8mm bolts holding the compressor bracket are sheared off deep inside the engine block holes. These will be fun to extract
This week a engineer friend with quality tools will help me remove the broken bolts. I will re-attach the compressor correctly, with a new belt.

Now I bagged my lines on day two.
At this point what do I have to do????

Get someone to pull a vacuum? and for how long 1hr or 24hrs?
Do I add oil to the compressor or wait for the recharge? What type of oil?
Is replacing the dryer a must? Does the dryer get its own oil?
Finally the easiest and most affordable recharge: r12 or freeze12?

And do shops fill with real r12 anymore? Everyone wants to convert me to 134....and I do not think they would even do that properly


I know AC questions are not direct and easy, but please do your best

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1990 300D 2.5Turbo, two tank WVO, daily driver 300,911
1992 E300 gaser, 150k. Parts only, For Sale

[B]1984 300TD Euro 4speed Sold
1977 300D Elsbett SVO single tank Sold
1981 300TD "Silver bullet" 285k ran B100 Sold
1981-5 300D x 5 cars stripped and reused, parts for sale

Other toys:
1995 Dodge 2500 Cummins 12V P7100 Bosch mechanical pump with 2 tank veggieconversion kit, only 120k!
1959 Cadillac Dad's legacy, needs finishing