Seeking arm suggestions for a Grace F9R

The range of acceptable resonant frequency is generally taken to be 8 to 12 Hz, not 10 Hz on the nose.  We'd be going even more nuts, if we sought an exact 10 Hz.  At 7 Hz, I repeat, do you have a perceptible problem? Speaking of footfalls, if you know anyone who tap dances at 7 Hz (that's "cycles per second"), he ought to be in a Broadway show.  The only way you'll hear an improvement, if you change tonearms to achieve 10Hz (or the acceptable range of 8 to 12 Hz), is if the new tonearm is simply superior to what you are using now.  

So, if you are estimating RF with a test LP, then you have an equation with two unknowns (Compliance and Effective Mass, but maybe not, if SS gave you a figure for compliance).  Assuming C and M are not exactly known, how are you going to calculate exactly what Effective Mass will move the RF up to 10 Hz?  Like I said, it ain't worth the trouble.  Also, because RF is inversely proportional to the square root of the product of C times M, it may require a very light tonearm to move RF from 7 to 10 Hz.  It's "LewM", by the way.

Sorry for mis-spelling your name LewM, it was a typing error.
Soundsmith did not provide a compliance figure. When I said 10, I was just picking the middle of the 8-12 desired range, not necessarily hoping to find a combo to get to it specifically.  Since I'm not hearing anything displeasing I think I'll leave it be for now and just enjoy it some more.
Thanks for helping me reach this conclusion.  And a superior arm to a significant degree is not in my budget at the moment.

This is how it looks with SoundSmith brand new stylus assembly.
*price list: https://www.sound-smith.com/parts/grace-f9-replacement-stylus

This is the Grace F-9F with nude Shibata stylus (RS-9F first generation rounded shape). It my old picture, not i have second generation of the FR-9U Level II styli (Line Contact).

here is a picture from the internet of the secong generation grace Ruby stylus (not rounded shape as the first generation). But the stylus is on ALL original Ruby is Elliptical: http://photos.imageevent.com/puma_cat/fujif31andf20photos/Grace-2.jpg

Dear @robbiesd: You own one of the best tonearm designs ever, way superior to any unipivot one. It's a very well damped design with great bearing design.

You can't be sure about that 7hz resonance frequency especially if you measured through those imperfect LP tracking tests.

As you said you are satisfied with the quality level performance with no problems at all that can been caused by that theorical 7hz resonance fr.. It's almost impossible that that 7hz theretical resonance can be precesily mated/even during playback coming from some anomalies in that playing proccess.

Even you can improve the quality sound performance level you have doing a internal re-wirin in the tonearm and with better headshell wires on what you are using in the headshell.

The EPA-100 is a very good design too and you can try with the Grace but in both tonearms the re-wiring is a must to do as the headshell wires.

No, I don't think that you need a different tonearm when you already own two of the best ever.

Regards and enjoy the MUSIC NOT DISTORTIONS,
R.