First off make sure the duo valve is not leaking. Then install a 134 expansion valve and dryer, make sure the compressor is not weak and charge the system by output temp, not weight. Also make sure there are no leaking elements and the car has the dual aux fan set up.
Then make your desision on going back to 12. I think if you get the system right it'll cool great.
Project Smoker, '87 603 powered wagon
Hauler, 96 CTD can you say torque?
Toy 73 Cougar xr7 convertible
Acme Automotive Inc.