I have a 96 Blazer 4dr 4wd 4.3L and have just replaced the orifice tube (variable) and accumulator along with all o-rings on connections that were separated. I also bought 8oz of PAG 150 oil.

I need to add PAG oil and have gotten differing information on how much to add. What I've found is a couple of ounces need to be added to the accumulator and 4 ounces or so to one of the hose openings on the compressor. I did not replace the compressor, so how do you know how much to add?

Do I add the oil and then vacuum the system?
Which opening on the compressor do I add the oil to?
Which opening on the accumulator do I add the oil to?

I know that the negative pressure on the system should hold for at least 10 minutes after the vacuum is turned off. During filling with R-134a, what should my low side AND my high side pressures read to be full?