Speaking here as the designer, and just to clarify a few things:
* The iron complement is IMHO of very similar sonic quality for Stereomour and Paramount.
* For 300Bs, only the Paramount iron is suitable (of course)
* For 2A3s the Paramount iron will perform slightly better in bass extension
* For 45s, the Stereomour iron will perform slightly better in both bass extension and in damping factor.
* The Paramount with 45s is not supported (not in the manual, not guaranteed), though it's been done by a few, notably Paully. There are changes using parts we do not supply, and several optional variants such as changing the iron. These are not documented except in various posts on the Forum.