Stumbled about this thread accidentally today. While I can't answer the original question, I can ascertain everybody in the forum that I had and still have the best CD-4 results with non Shibata good quality MC cartridges like Ortofon MC-30 Super and similar with Van-den-Hul or other "modern" styli plugged into a MCA 76 before it goes into the CD-4 demodulator. I recently compared this cartridge to a AT-20 SLA, which is for many the best CD-4 cartridge, on the same arm and turntable and the result was so much in favor of the MC-30 that I probably will start to offer all my original CD-4 cartridges soon. None of the difficult CD-4 records like Barry Manilov or the last track on BW Stevensons Calabasas are a problem with such a MC cartridge.
When I started into Quad more than 20 years ago I tried an MC-30 accidentally, because it was mounted on my turntable and the results were good, but I didn't know how good because I had no comparison. When I learned more about quad I bought and tried many of the CD-4 cartridges, most of them were still new. The results were not so good and for years I've blamed my setup for it. But now, since more than 2 years I've returned to the MC-30 again and CD-4 was never better!:sun
I too have had the best luck with a stereo MC cartridge, a Sony XL-MC3. The carrier never drops out on any records I've tried so far, but still the recovered audio is not as clean as I would like. I recently purchased an Othofon SL-20Q which is a vintage moving coil CD-4 cartridge, I haven't tried it out yet, I also have the Othofon MCA-76 pre-preamp (with the CD-4 filtering switch). I think that because of the lower impedance of moving coils vs moving magnet designs cable capacitance is much less of a problem. Still I've ordered a capacitance meter and so will be able to check the capacitance of all my turntables & cables. I've never tried using a purpose built CD-4 turntable but I might eventually try that as well, as some are selling on eBay. I've always thought that CD-4 was much too finicky a system, if any detail is wrong you get poor results. The Marantz CD-400B is the best demodulator that I've tried, but some complain about the automatic carrier level, so I might revisit the JVC 4DD-5.