OK, system reassembled using the original condenser. New drier and all O-rings installed after a complete system flush. Pulled a vacuum of ~-28psi. Ran the vacuum pump for over an hour. Waited to see if I had any leaks but no visible change in vacuum for over 2 hours. Ran the vacuum pump again for about an hour and shut it down for the evening. This morning I checked pressure and found it to be a little higher vacuum at closer to -30psi. Guessing it was a difference in ambient temperature since the morning was cooler.
Plan to inject the Freon next we. Waiting on a couple of items to arrive before I begin the charge process. I'm waiting on an oil injector to allow me to put in some Red Angel Stop Leak
as a preventive measure. It's the only stop leak that appears to be safe for R12 and non-clogging. I'll also inject some UV Dye just in case.
I can't find any labels to indicate fill volume but I do have gauges and will use that to predict final fill. Last time I did the AC service I think it took about 32oz total of Freon. I'll be adding two 14oz cans of Freon along with 1 4oz of Freon oil charge. That should replace the oil that was lost during the flush and give me the 32oz total fill volume. If anyone knows for sure what the total amount should be, please chime in.