I started playing around with alternative condensers a while back for these things, first it was the paralell flow jobs which are suposedly the bees knees, which are still round tube , but about half the diameter of the stock tubes and about 2-3 times as many in a stacked pattern to allow more surface area exposure between the refrigerant to tube wall to flowing air > I have one of these on my crew cab with the dual ac system( rear air ) and it works very well , but in the constant search for something better with my regular AC supplier ( Jon at
www.nostalgicairparts.com , and he can get you top quality condensers for these things that will have you blowing snotcicles , He keeps the part numbers handy for these trucks as when we were working these things up, he kept the numbers handy for you guys) but later we tried the serpentine condensers on some others and they cool WAY better than the parallel flow condensers as there is no dead flow in the middle of the tubes as there is even with the smaller round tubes of the parallel flow jobs ( and the massive dead flow of the stock ones ) the thin tubes of teh serpentine condensers allow for all of the refrigerant to get maximum air flow across it throughout the entire pass, it doesnt get any better. ( very similar to the plate and fin tranny cooler design that works so great and much better than the tube and fin )
If you combine a serpentine condenser with a VOV you should have no trouble at all getting 33-35 deg duct temps