Cartridge/Tonearm Matching

I own a Connoisseur BD2a with a Grace tonearm (low mass). About a year ago I was going to replace my old Goldring cartridge with a new Goldring 1042. However, I read about the Dynavector 10X5. My local dealer highly recommended the Dynavector and installed it for me. Now I am reading and learning about compliance between the cartridge and tonearm. Based on my initial understanding the Dynavector and Grace do not match. Did my dealer steer me wrong ?
Technically, the low mass Grace 707(if your Grace arm is in fact, a 707) would not be a very good match for the 12cu compliance of the Dyna 10x5. It would put the mass/resonance figure outside the "optimal range".

However the Grace arms have good bearings, and can handle the stiffer compliance of this cartridge pretty well.

So, if you are not noticing any serious resonance faults in the audio band, perpetrated by the cartridge/arm matchup, you could get away with it.

There is a good chance that you are also losing some dynamics and low end, due to unwanted tonearm movement caused by the light arm and stiffer cartridge.

I think the Goldring 1042 was a much better match for your arm.

Until I looked it up awhile back, I also was under the incorrect impression that the 10x4 and 10x5 cartridges were higher in compliance than they actually are. The 12cu compliance is actually on the "stiff side" of the medium compliance range, and could be considered low-medium compliance.
I am p- off that a my local reputable high end dealer would sell this bad match to me. I am thinking of replacing it. Are the Shelter 501 or 901 high compliance ?
No, the Shelter is going the opposite way. They are lower compliance.

If you have the Connoisseur arm that was standard with the BD2A, and not a Grace tonearm, then it may be a better match with the Dynavector. The Connoisseur arms were heavier than the Grace 707.
Based on pictures on the web, I think you are right TWL. I think it may be a Connoisseur arm. I sent an email to Sugden. Would the Connoisseur arm have been low or medium mass ?