AT-ART9XI Cartridge - Reduced Compliance

Avanti, lots of praise on Audiogon for the XA.  The SME V is higher mass than your arm (10-11g) and, unless I swap out a couple resistors in my Classe Six, the gain would only be 57db.  As you mentioned back in August, the XI would probably work better with my arm, and I wouldn't have to mod the Classe.  The SME is due back in 3 weeks, so I have to pull the trigger soon.  The XA sounds so enticing I'm still in a quandary.

I have no doubt that the XI is nice but listening more today of the XA, I would not want any more bass or warmth.   I suspect the XI has more of this. 
Everything sounds great on this cart. 

Is it that big of a deal to mod the class to see 64db?    

It's an easy swap of two resistors on an old school board.  The manual has a detailed list of resistors for fine tuning the output in 2db increments, so I could choose +63, +65, +67, etc (up to +75!).  Pretty dang thoughtful of Classe.

Truthfully I'm more concerned about the SME's mass, which is technically in moderate territory, but just barely.  The XA wants a low mass arm.  Your arm is 9g, mine is 10g with the lightest hardware.  Maybe I'm over-thinking it.

What's the best way to increase the effective mass of the SME V if I select the AT-ART9XA?  The XA's dynamic compliance is only 10, and it weighs 8.5 oz.  Without increasing the SME's effective mass (10-11g depending on hardware), the resonant frequency would be a bit high.

It seems the effective mass should be at least 12g for the XA, according to Vinyl Engine's chart.  Is there hardware available for this purpose?  How is the proper weight to add determined?

https://www.vinylengine.com/cartridge_resonance_evaluator.php?eff_mass=12.0&submit=Submit

@keegiam 
per the Audio Technica web site you can multiply the 10um compliance by 1.5 to 2X to calculate compliance at 10Hz.  

This is the first time I have ever noted an manufacturer's compliance conversion formula in print.  

From AT:
To determine where the resonant frequency of a particular cartridge/tonearm combination will occur, you must first know a few things about your equipment. You will need to know the total effective mass of your turntable’s tonearm assembly, the compliance specification of the cartridge you are considering and the weight of the cartridge. Note that Audio-Technica specifies compliance at 100 Hz. Many resonant frequency calculators, however, use a compliance measurement taken at 10 Hz for their calculations. To determine the compliance of a cartridge at 10 Hz when only the compliance at 100 Hz is stated, multiply the 100 Hz measurement by 1.5 or 2.0. Once you have gathered this information, you can determine the resonant frequency using a resonance calculator such as the Cartridge Resonance Evaluator tool available at vinylengine.com. Enter the tonearm effective mass figure into the text box on .....

https://www.audio-technica.com/en-us/support/audio-solutions-question-week-determine-audio-technica-...