There is so much junk going on with the tonearm cartridge thing that one needs to get involved to get it right. I just put together stuff that might work and don't worry about the complete acceptability of the system components.
This comes from years of having separate tonearms and decent cartridges. Ideally, one will match a low compliance cartridge to a very heavy tonearm and a high compliance cartridge to a low mass arm. I've done this with some gear I have picked up. One a Kenwood KD-600 with one if the heaviest effective mass tonearms available back in the day a Fidelity Research FR-64s, a 34 gram effective monster. Compare that to the very low mass ∞Black Widow at about 3.5 grams effective mass.
These two arms will not extract the most out of a cartridge that works well with the other arm. Fortunately there is some data over on the engine that will help provide info if one is so inclined. I use the data but not to decide on the arm or cartridge as those are pieces I already have.
With the low mass arms, there are fewer cartridges that work well with them, different than the old days when Shure made high end cartridges. Additionally, the moving coil cartridge, generally requiring more amplification, is more popular today than in the past and so more folks need the medium mass arms that get the most from these cartridges.
One of the main goals of this matching of tonearm mass and cartridge compliance is to obtain a resonance of the combo between the low 0-2 Hz of the record warp and the lowest frequencies on the record, ~20Hz. So a resonance of say 8-12 Hz is recommended.
So there are reasons to have a nice heavy arm and a very light arm. Whether it is straight or not doesn't matter if the stylus is at the right position to play the record correctly for the arm.
