I agree with The ViKing. Someone with experience actually getting his(her?) hands on your system.
Before anything be sure that oil traps (with or without risers?) installed properly and check the height difference between the evap and the compressor. You must also check the level of refrigerant in a proper way. Also check the temperature on the head of each compressor. Is it too high or cold? Too cold is an indication that maybe liquid refrigerant entering the compressor.