[Ortofon X3MC] really sounded screechy.
I haven't had much MC experience, but, going by my memory of things I've heard said, there could be a couple of other issues at work, too:
-the cartridge might have benefited by more break in time. This is important for MC cartridges, I've been told. In fact, I've been warned that if I ever move to a MC, I should expect hours and hours of painful listening with at least some MC cartridges.
-the cartridge is, I think, high output moving coil, and that might be part of the problem. (Although I'm under the impression the Ortofon designs might be better behaved here than, say, a 1st generation Sumiko Bluepoint.)
Although I'd say, at a distance, I wouldn't expect a MC to work well on low mass Dual arm.
But one never knows without trying. I have an old Dual lying around. I can't remember the model off the top of my head, but it was one of the cheap semi-automatic models. It came with an Ortofon MC installed, and when I saw it, I thought that it was probably the dumbest idea ever. I honestly didn't think the arm would be suitable. I'm not sure about the mass, but I assume it's lowish. Plus I can't imagine the arm bearings are particularly great. And I'm pretty sure the cartridge is probably "too good" for the turntable.
The turntable was dirt cheap, and I got it to play with. Since it's used, with no known history, I only played records I didn't care about. Mostly older, worn. I didn't have the chance for exhaustive tests, but what little I heard surprised me. The cartridge seemed to track OK, and I didn't hear anything really "wrong." More listening might have brought up other problems...but doing as well as it did was more than I expected.