Teflon washers for cart, were can I get these?

Try McMaster-Carr. FWIW, I've always preferred the sound with metal washers.

I replace one washer at a time. That way the cart doesn't move and no need to re-align, just check VTF. I use an allen wrench and go to "two finger" tight without strain. I want my cartridge to be rigidly mounted so that it becomes a single instrument with the tonearm. The idea is to allow the tonarm, base, turntable, etc., to handle the vibrations as a unit. Any material between the cart and arm that would affect how vibrations move into the arm will affect the sound.