Have had both carts in my system so maybe I can add something other than speculation. I have to say, interesting if not odd cart choices. I don't think you could have two carts (Puritas and Koetsu) that could be much further apart on the sound spectrum. One is very energetic and one very smooth. Both have great detail retrieval but those details are presented in two very different ways.
The Puritas sounds very good on a 12" hardwood Reed arm. No sibilance. Would it sound better on a heavier arm? Maybe, as the Puritas is rather stiffly suspended. I did try a Puritas on a Fidelity Research 66 arm which is high mass. The sound was different but I would not say it was particularly better overall than the Reed.
The Coralstone was very happy on the FR 66. I mean REALLY happy.
The Puritas sounds very good on a 12" hardwood Reed arm. No sibilance. Would it sound better on a heavier arm? Maybe, as the Puritas is rather stiffly suspended. I did try a Puritas on a Fidelity Research 66 arm which is high mass. The sound was different but I would not say it was particularly better overall than the Reed.
The Coralstone was very happy on the FR 66. I mean REALLY happy.