Todd,
If I'm remembering correctly, the S-8s were something like 98 dB sensitive which should really rock with the 2a3 Stereomour, no problem. 45s will also go quite a long way too, and depending on room size, musical tastes, etc., should also be fine. Of course I have no idea what the impedance and phase curves look like, but we'll assume it is a SET-friendly design considering where it comes from.
HTH,
Jim