Decided to try a SPU cartridge

@kennyc 

The Viv Lab's definitely work with SPU G's, just remove the headshell and pop in the SPU, although I would argue the Royal N sound's better than it's G equivalent the Royal GM II, and it's cheaper as well.

@alan60 

Thanks for the tip regarding the smaller sized "N" SPUs. I'll keep that in mind - maybe later I'll further explore optimizing the SPU sound.  

I like variety.  I'm in my 60s.  Because I started late my high end audio,  I'm kind of condensing my high-end audio experience tempered by my wallet as my remaining years seem limited.   The SPUs is a side interest as my main system is neutral linear.  I'm also building a fleas watt system to explore tube magic aka harmonic distortion :) - I purchased a 300B amp already and need to budget for a flea watt speakers.  

First of all I really love the SPU sound. Actually I own a GM E and a Synergy.

They give a fine contrast to the sound of my different DS Audio cartridges.

For the "normal" SPUs you should work with a SUT to get most out of them.

My Synergys don´t need that. They offer the best sound with a MC-phonostage

and between 33 and 47 Ohm.

The match of SPUs with a ViV Rigid Float is a perfect one. Balancing and

adjusting is an ease and they singing in the best possible way.

The reason why ViV is not mentioning the effective mass is the fact that

this doen´t matters. The oil bearing of the arm makes them suitable for

all kinds of cartridges. I personally tried many different cart from light

MMs (Grace, Victor, Ortofon 2m...), heavier HO-carts (Jico Seto Hori, 

Acoustical Systems Fideles...), lightwight MCs (ZYX), normal MCs 

(eg. Ortofon Vero, Ortofon Cadenza) up to SPU As and Gs.

ALL of them sounded the best way they can. -> perfect match

@kennyc 

IMHO you should be using an SPU in your main system. I am also in my 60's and have only just joined the SPU party having been down numerous other roads before. The beauty of the Royal GM II or the Royal N is that they use the Ortofon Replicant Stylus, which is a modern profile able to retrieve the maximum from the grooves, so you get the joy of what the so called 'old MC technology' brings along with the detail of a modern cartridge.

One question for those more knowledgeable about stylus profiles, I have heard the Ortofon Replicant Profile is the same as the Fritz Geiger, is this correct?

@dover 

Also, just to reiterate, if you want to play with SUT's, you can use them with the MM input on your Grail phono.

The GrailSB is a "current" phono stage.  Not sure if the MM inputs are "voltage" based which would allow a SUT.  My Grail is still boxed along with the rest of my gear. Awaiting funds for interconnects and speakers to complete my analog+digital audio chain.  Wife not to thrilled to see my audio spending resulting in boxes.  I have to change flooring (duct tape fix not good) so incentive to wait till done.

@alan60 and @racedoc

Thanks for your input.  I like the ViV arm since it's sonically different than other arms in a positive way.  It's very comforting that the ViV will work well with SPUs and other carts.   I was on the trail of a dedicated SPU tonearm - Groovemaster II vs a Bokrand modified Ortofon RMG309 (or RMG309i).  

I have a VPI Avenger that can accommodate 3 arms.  Besides the SPU, I was planning have to get at least another tonearm likely the Kuzma4point to accommodate my other low output non-SPU MC carts .  Although the ViV can accommodate all carts, I'll likely get both the ViV and the 4point - removable headshells for quick change (after the cart was previously set-up) seem very appealing. 

I just picked up 2 more used Ortofon GM SPUs - the E GM GOLD and the Classic GM E MkII.   The Gold's sonics reportedly falls between the Meister Silver and Synergy.  The Classic E will give me a taste of the early SPU sound.  So I'm pretty much done with sampling Ortofon SPUs with the exception of the Wood.  

I also picked up a used FR7-fz cart from Japan auction with a broken cantilever.  Happy I got it at a relatively low cost as I'll upgrade the cantilever+stylus anyways.

If I go SUT, the consensus is that silver is best  - unfortunately it's a significant jump in price vs copper.