I will chime in for some feedback on this subject as I too run the most fabulous Whest PS 30 RDT SE, 2019 edition with some custom build stuff from James at Whest and many of the PS 40 RDT components.
I run a VPI Ares 3 with the super platter and the SME Series IV tonearm. I have two carts which sound simply amazing with the Whest, the first is a vintage Audio Technica AT20ss MM with a NOS OEM super shibata stylus on a beryllium cantilever, the real deal from the factory, not an aftermarket item; I luckily have several in the box NOS AT20ss stylus' on hand. Whest built one input on the phono stage with a perfectly matched capacitance and gain for the AT20ss as James Henriot also owns one of these cartridges and it's his go to MM, he knows it well. If you can ever find one of these MM pieces, buy it. My other cartridge is an Ortofon A90 MC, and it is simply stupendous. It plays just like the AT20ss, lots of gusto, detailed mid and upper end but with very strong, articulate low end. The A90 MC is more open on the upper end and its' a little more detailed, but the AT20ss is about 90 to 95% of the A90 MC. You might be able to find a NOS or very low time AT20ss for around $1K if you got lucky, or you could find a used A90 MC with low time on it for around $2K. James at Whest also uses the A90 and A95 as his MC selections and he told me that when the stylus wears out to send it to London to Expert Stylus to have their Paratrace cut installed, he said it elevates the A90 to another level. I take his word on this as I have found the Whest phono stages are the best that I personally have used; they make bullet proof gear.