these people make a separate VTA mechanism for SAEC and Fidelity Research Arms.
To be precise, I would like to underline that Epa 500 is only the common base for all arms compatible with this.
each arm has a limited range of compatibility with the cartridges to be used depending on compliance
I own a B500 with the EPA250 arm wand and a 501H. Unfortunately the base is so "fat" that it really will not fit any of my turntables except my TT101. But I have an FR64S mounted on the TT101 specifically for low compliance LOMCs. I'd have to machine a new tonearm board for the B500. (I use a solid aluminum armboard that is further braced from below by fastening to an even larger piece of alu.) But the B500 is an esthetically beautiful piece of precision engineering the likes of which would cost a fortune in today's money.