I know cartridges are a world in itself. I would just start with the most inexpensive MC cartridge that would be compatible with the Concept turnarm.
The Denon 103r should work. Dirt cheap here. Plus one of the reviews of the Coincident asserted that it plays well with the Denon.
I find that there's such a thing as over-deliberation. Even in the absence of all the facts, sometimes one just needs to make a decision, one way or the other, and move on. Moreover, you now have 25 records (and counting?); give them some love.