Success!!!!! Thanks all who chimed in!
For others who may find themselves in a smiliar situation, heres my error & fix:
after reading the 52 and 54 manuals, I realized it shouldnt be this hard.
The two things I did different that seems to have worked are 1) used some rubber wedges to keep glass centered in the door, 2) removed the two screws at the back of the door holding the back channel rigid. This gave me enough play to angle the glass, keeping the glass in the back channel and drop the front edge of glass into the front channel once I had the vent assembly in place. Minimal "twisting", just slight angle on glass and front channel.
Thanks again, I really appreciate this forum!
