Converted a/c to r134, not cooling well

[swb85]

I just replaced my compressor, drier & orifice tube and converted to r134. I pulled a vacuum on it for 45 mins and put 3 cans (36 oz) of freon in. The r12 capacity was 44oz, but from what I've read r134 takes less freon. It hardly cools the air at all, even at max a/c, fans on high and at highway speed....vent temps feel like only in the 60's.
I'm getting all sorts of condensation on the drier/evaporator when it's running and it's cool to the touch (not cold) so I know it's "working", but it's just not getting very cold at all. I see 25-30psi at the low pressure side. Am I over/under charged? Any suggestions? I know little about a/c, so I'm wandering around in the dark here.