Hey David,
I have the same plans for the near future...getting a TD124 with a 12" arm, but I now have a 3012R on my Nouvelle Platine Verdier wich should be replace by a EMT 12" therefore the SME should be mounted on the TD124.
For the beginning a SPU classic will do a good job and it's a timeless classic, which makes you forget about hifi. Once I heard a set up of TD124, SPU classic, 3009 and Croft tube electronics on Harbeth speakes at the AAA-Forum (a exhibition mainly for vinyl playback) an this was the very best sound on show, even compared to "all out" installations costing significant more.
One thing to take into account is the right phono amplification, step up transformer. I use the Auditorium23 Hommage T1 and Audio Note Japan AN-S6c and tried a lot of others. The difference are not subtle. It needs a good matching trqansformer to really make the SPU "sing" On my former Gryphon Orestes phonostage I never liked the SPU classic as much as with a good step up over my Paragon 12a tube preamp.
Best regards
Ron