Disclaimer: this particular operation was on my rb67-545i back. A 545 holder which doesn't already fit on your rb won't fit any better after this operation! This operation is to make it easier to use Fuji quickloads with your545 back.
I have a
Polaroid 545i back for my
rb67, with which I have been shooting type 55. Now that 55 is leaving us

and I have only a few boxes left, I'll just use my remaining 665 for the rb and run Fuji quickloads through the Polaroid back. Seems like...