Not to disagree with the other carty advice above, but I agree with Stringreen's advice that you should check with Mike at VPI before putting cash down. As I've mentioned in other threads, I pulled out what little hair I have left trying to match 4 cartridges to my Classic 10.5i arm. The best fits turned out to be the Sound Smith VPI Zephyr and the Dynavector 20X. These cartridges list for $1000 and $850, respectively. As I recall, the compliance ratings of these cartys are 10 and 12, which I consider on the low side.
The 3 other cartridges that I bought, tried and either resold or returned listed for $570, $$975 and $1250. For me at least, that's a lot of $$ to just "try out."
I think one of the design aspects of the JMW arm that makes cartridge selection a little more complicated than just checking effective arm mass and cartridge complaince is the uni-pivot arm.
Now, Mike has previously told me that the JMW arm can be made to work with just about any cartridge out there. That may be true. . . . but how much grief will go along with making the match. The nice thing about the VPI Zephyr, which was designed for the VPI arms, is that I slaped that sucker in and started to spin vinyl. No grief. The DV was also an easy install.
So if you call Mike, ask him if the cartridge you want is a "slap and play" type or a "bang your head against the wall" variety. IMHO, I'm not interested in sending the cartridge and arm to VPI for a custom install, which Mike does from time to time. FWIW.