Turntable advice / opinion on setup / sound.

Elliott, I can’t help you.  AFAIK the information you seek is not available.  Rega is not interested in making their arm or their turntable compatible with other cartridges.  If you take the time to research the design philosophy of their products you will learn why.  Mikey Fremer did cover the subject quite thoroughly, first in a multi part video visit to the factory that is available at Analog Planet.  Separately he has reviewed several of their turntables in which he also covers their design philosophy.  For our purposes here, perhaps the best I can offer is to say that although their products seem to work quite well, they are best used as directed.  That is to say, used with either their own cartridges, or with ones designed specifically for use with them.  Although I have not had the opportunity to measure the performance of a Rega TT with an Ortofon cartridge, based on the respect I have for both companies, there is little doubt that they would mate up and work just fine without the need to do anything other than set VTF.  That is exactly the way Rega designs their products to work.   I am confident that Ortofon took that into account in the design of their compatible cartridges.  It is worth noting that even though this approach is clearly not directed at sophisticated consumers like you, it provides the majority of people an opportunity to enjoy top level performance without needing to know any more than how to unpack their new unit and plug it in.  Actually, I would like to correct something I communicated in my previous post.  Although the Rega Naia would be my first choice, if the right deal comes along, I would not rule out a P10 either.  These are really terrific turntables and worthy of even the best systems.  You should take time, try to erase the prejudice you have developed, and with an open mind at least take the time to understand the great thought, effort, and on going refinement that has gone into what is a very innovative line of turntables.   They may not be for you, but they are worthwhile and should not be dismissed lightly.

The top of line Rega with Lyra Aetna I listened to at buddys house recently was setup using IEC protractor.. A Brinkmann in this case but a Clearaudio or a sturdy but well worn vintage Denneson would suffice.

the dog in this particular fight sounded great from a whisper to a full on Satchmo howl

There was no fight and I don’t own a dog. I take the position of Sgt Friday, just the facts. What Bill wrote about the Rega approach is no BS. Maybe there is good sense in their method, as they reduce the possibility for customer error resulting in an unsatisfactory listening experience. That in turn makes it less likely they’ll be subjected to unfair criticism .

I am not familiar with your phono stage but if your MC cart is a low output then you need a phono stage with a 60db gain setting.