LONDON Decca, Tzar DST and similar cartridges


I have always been curious about these phono cartridges and the Stereophile review of the Tzar DST has heightened my interest. When I read about the peculiarities of these cartridges, I am put off from trying them. Can anyone offer persuasive reasons to try them and also provide real practical advice on how to make them work reliably?  Tonearm suggestions? Phono preamp suggestions? Damping recommendations? How badly do they grind out record grooves?  Any other words of advice? Thanks. 
kmccarty
I just came across this old thread and as an owner of a London Decca Reference I thought I'd respond.  I've had mine for a couple of years but have always loaded it at 47k.  I was interested to read the suggestion of loading it at 15k.  I'll give that a try.  Thanks.
I spoke to John Wright on the phone and by email, when he rebuilt my FFSS MkIV C4E with a fine line tip. He told me to load it at 33k. hence I had Graham Tricker build me a TRON Seven Reference to match this. GT spoke to JW as well just to check before he built this for me. Great match and sounds fabulous. But just not as good as 1/4 inch 15 IPS master tape, but hey LPs are a lot cheaper :)
That's the cartridge I'm looking for myself, topoxforddoc. I already have a London Super Gold with Decapod and a Reference, but the Decca MkIV C4e has it's own, unique, qualities. Regarding the loading of the Reference, John Wright himself recommends running it at 15k ohms and with about 220 pF of capacitance. That's the only way I've heard it.
I’ve ordered the DB Systems DBP-6 MC Phono Resistor Loading Kit to run the Decca Reference at 15k ohms. And by adding a 130pF cap I can bring the capacitance up to 220pF.
I’m curious:
What sonic differences have others experience when running it at 47k and then at 15k?
The 15k impedance in combination with the added capacitance creates a damped electronic circuit. The Decca/London design suffers from an inherent high-frequency resonant peak, plus ringing in the time domain, which the damped circuit addresses. I was tutored in all things Decca by the Master, Harvey Rosenberg.