Need help with phono cartridge selection


I have 2 Dynavector phono cartridges. Ultimo 20C and Ultimo 10A. I know that the 20C is a low output MC and that the 10A is a high output cartridge. I have sampled half speed mastered vinyl with both mounted on a Denon DP 30L II turntable and have experienced pluses and minuses with each cartridge. I am using a Hafler DH500 amplifier with a PS Audio 5.6 Preamplifier for electronics and Snell Type A loudspeakers. Simple question...with this setup... which cartridge should I keep ? Ultimately my ears must be the judge and I understand that, just looking for opinions.
rettuc01
How old are these carts? I haven't heard of either one. Are they similar in age to your Hafler and Snell (25+ years old)? If so, the rubber suspension has probably deteriorated. I'd have them checked out before using.
They are late 80's models...but I purchased them recently new in the box. I examined the stylus, cantilever and housing and they are spotless.

There is some blog info out there about the 10A...but precious little on the 20C. The 10A retailed for about $ 390.00 and the 20C was around $ 550.00. They both have very dynamic sound reproduction qualities and I have the orginal spec sheets and independent test metrics. I am just not that knowledgeable about high versus low outputs and their interactions with the equipment I own. The Preamplfier has a MM/MC switch in the rear that is tied to a phono stage in the chassis so I am able to utilize the MC cartridge...but I don't have the paperwork any longer for the Pre so I can compare specs for it against the cartridge.
Retuc01 - charts and graphs mean very little. The cartridge sound is the important consideration. If you like it fine, however, the fact that it is so old is suspicious. Rubber parts deteriorate from ozone in the atmosphere...things harden and soften.... I would have it checked out by Dynavektor..it probably needs a rebuild.
You say you have heard plus and minus'with both cartridges. Neither will have value in the re-sale market.
Therefore the simple solution is KEEP BOTH OF THEM