R-12 has a pressure temp relationship that will have it at over 100psi on a summer day. If your system has only 35psi on the high side, you have almost no refrigerant in the system.

As to your procedure for evacuation. Unless you are on the top of Everest on a 100deg day, you are not doing the job with only 25in of vacuum. The concept you are trying to achieve is that you are wishing to boil the water at ambient temp. This gets easier at altitude but at sea level and a 90 degree day thevacuum that must be pulled to make the boiling point drop below 90 degrees is closer to zero psi absolute than standard gauges will tell you. one needs a micron gauge to view the actual level necessary.

The concept is to lower the pressure to the point moisure is boiled at ambient temp and then time is needed to finish the boiling.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician