This is a How to DIY Video on Ductless Mini Split single dual four zone units. Also Air Handler and Evaporator The best method of putting  410a freon in a Compressor is by weight period. 
Tightening Torque Table:  
1/4" 11-15 ft. lbs 
3/8" 23-26 ft. lbs 
1/2" 37-41 ft. lbs