dang2484 it’s your call at the end of the day but just because both fit in the SJ doesn’t mean both will fit in the T64, the SSP also fit the DF64. Mazzer burrs just seem to have an irregular inner burr size, some people tried the newer burrs from the Philos in other grinders and also couldn’t get them to fit.
Then again the T64 carrier may fit, so do report back if you try!