Condensor For ''89 Camry

I had my car''s A/C compressor replaced and it is now using the R134A but my mechanic told me that since the lines on the condensor are bigger, the freon will move through the system alot quicker therefore not allowing enough heat to be drawn in when at idle or stop and go traffic or driving real slow and so the A/C will not get stay cold during these times.

He said he tried to find an aftermarket condensor that will fit and work on my car with smaller lines but could not find one.
Any suggestions on where I might find one?

Thanks