Andrew
I have a 1988 245 that i am going performing the conversion on. My first try gave me results like yours. I found that blowing air through the condensor was not enough to "empty" the old junk out. I use a small air gun to blow it out. apperently a low pressure air gun can blow air through it without removing old stuff. In frustration I ordered the volvo kit and started over. This time the air gun was not available to me. Using just a coupling on the air hose i used full force air to flush out the condensor. A large amount of trash came out this time. In my case the first charge (even though it had been evacuated for over an hour) was still contaminated with r-12. After this I am getting uper 40's on temp. Now if i could only find the leak. By the way my pressures are (with auxillary fan) 225 and 30.
Good luck
Joe Scott