Any a/c gurus out there-problem with mine?

[Botietruck]

Anyone familiar with the stock a/c system? I am having a few problems with mine and I am looking for some guidance.
The system has everything new. Condensor, evap. core, dryer, POA valve, expansion valve has been reconditioned & tested, new hoses, fan clutch, etc. After pulling a good vacuum and charging it with 134a -about 44oz., the ambient temp @ 85-88, I am getting 255 on the high side, 38 on the low side and vent temp is running 52 degrees. The engine is running at about 1500 rpm. The sight glass is milky. I was hoping to get about 45 degrees out of the vents. Here's my problem, after running the engine for about 30-45 min. I shut it off for about 30 min. to eat dinner. Came back and the compressor acted like it had pressure on the system, It would barely turn over by hand. I left it sitting for about an hour or so and came back and the compressor would turn free. Any thoughts?