On my 84 300SD, my low side reads 40 psi. Shouldn't the metal line feel like 40 degrees? I have 68 degree discharge air with 90 degree ambient air. Could I have too much oil in the lines?

When I originally bought the car, the oil would bubble out of the schaeder valve whenever I removed the gauges. I knew then there was too much oil in the system. I flushed the system with an air gun and got quite a bit of oil out of the condenser, evaporator, and compressor. I put 4 oz in the compressor, 2 oz in the evaporator and 2 oz in the condensor.

Could there still too much oil? How is the best way to get all of the oil of the system and start from scratch with new oil?