My model 20 did not have any bushings when I disassembled it. I don't think the 21 was much different chassis-wise. Shim it with the hard rubber washers if that's what it takes to align it to the cabinet. None of us are going to come down on you for it. I for one believe in the "whatever makes it work and not look obvious" approach. Take care, Gary
"Don't pity the dead, pity the living, above all, those living without love."
Professor Albus Dumbledore
Gary - Westland Michigan