The FR64S has the highest mass, while the FR64-fx has somewhat lower mass. Both FRs are long out of production. The S-series is more sought-after, but tends to sound worse unless you need the extra mass (damping the armtube helps significantly).
The Ikeda IT345 is closer to the fx than the S, and it can be had in a detachable headshell version (like the FRs) or with integrated one-piece armtube. Build-quality is better than that of the FRs, and I like the sound better, too (even the detachable headshell version). The Ikeda is currently in production, so you simply need to locate a dealer.
All of these have dynamic (helical spring-loaded) VTF capabilities. hth.
The Ikeda IT345 is closer to the fx than the S, and it can be had in a detachable headshell version (like the FRs) or with integrated one-piece armtube. Build-quality is better than that of the FRs, and I like the sound better, too (even the detachable headshell version). The Ikeda is currently in production, so you simply need to locate a dealer.
All of these have dynamic (helical spring-loaded) VTF capabilities. hth.