73 Valiant R12 AC system pressures

The car is new to me as of April 13th, prev owner said the expansion valve was replaced which it has. To check for leaks I filled the system with air from my compressor, there are no leaks by sound and on the gauges. So I then Vacuumed the system for an hour and let it sit for 2 more and it held about 28 hg. Filled the system with about 3 12 oz cans of R12. I believe it is still a little low as the Factory manual calls for 2lbs 14oz Which would be 46oz. I have 1 12oz can left. My main question is what were normal pressures as I usually go off of that when filling my 134a systems. R12 is new to me as this is the only car I own that uses it still and I know it runs at different pressures than 134a. My main concern is I do not want to over pressurize the system.

The coldest duct temp inside the car I was able to get it at was 97 degrees outside temp and blowing 68 inside the car this was while driving and getting the speed up to 50+ MPH. The condenser is clean with no blockages.

The other thing in regards to the pressure surge, when the AC is on the Max AC setting the compressor always stays on and I never hear it click on and off. It will however click on and off it is on the AC setting. So that video I posted with the bouncing low side, the compressor clutch was engaged the whole time.