But it handles my FR1Mk3F’s 0.14mV easily — in fact, with the volume on my preamp at only 8 o’clock, it’s blasting. Your 0.2mV Spectral should be fine — though its impedance is wickedly low.
Your dilemma is superior SQ (though not by much) vs Versatility. If you’re like me, I’d go with versatility... but always feel something’s missing, now that I know what’s ‘not there’. I’d always miss that extra ‘something’ and inevitably go back to the CST. But you have two great SUTs, and that’s not a bad dilemma to have. Our pursuit of the divine in music is fraught with dilemmas.
You can buy, or make, a switch-box to handle more turntables — but will that degrade SQ? A bit, probably — the FR’s switching capabilities may account for it’s slightly lesser clarity.
Even though its captive leads are old I’m sure they’re good (it’s FR after all; they used silver coils in their MCs at the time). I’m not sure replacing them with RCAs would help. At least the old leads are a direct signal path — yes, you could use “better” ICs, but chopping the signal up with additional solder-joints and plug connections might nullify any benefits a “better” cable could give you.
You’ve probably seen this review/lab-test of the CST when it was produced; it contains thorough data:
http://www.gammaelectronics.xyz/audio_12-1982_audio-interface.html
The site is also an archive of old reviews of serious equipment, fun to leaf through...
PS — No need to apologize for the long post — it wasn’t long enough! I'll be very keen to read your further ruminations and conclusions...