Matt - you are correct, however, with the addition of a 7gram brass heashsell shim they are a very good match to rega style arms.
I have two 103's, each epoxied to a 7 gram brass shim and they perform extremely well on my Audiomods arm, but even without the shim they are pretty good
Other alternatives include
- the Zu 103
- various aluminum headshell casings you can place the nuded cartridge into
- soundsmith wood body with brass shim - getting expensive though
Sunnyjim - you can always place a 7gram blob of bluetak over the cartridge teporarily just to see if you like the sound of the additional mass.
Regards