A/C system pressures

[LEEVON]

'87 Silverado, a/c history unknown. The system was empty (no charge), but closed and I found the compressor low pressure switch to be faulty. I replaced the switch and added 22oz. of R134a refrigerant. I didn't want to overcharge, so I went to the conservative side of the charts I could find. Problem is, I'm sure every system is different and I don't have a service manual.

Ambient temperature 85 degrees. A/C on max, idling at 1500rpm for 10 minutes, I'm getting low side pressure of of 40-45 and high side of 200-215. but the vent temperature is 60 degrees. I noticed the compressor clutch never cycled, idling or out driving. I'm thinking that can't be good! I wonder if the high pressure switch is bad or what?

What is the recommended pressure for this system? If I'm on the low side, should I add a few more ounces or assume that I have bigger problems like a clogged orifice tube, bad compresor or contaminated system? I'm hoping to limp it along until I have the time to go through everything but if adding a little more.