Steinmusic SP 1.1s for my Wavac MD 300

Hello Normie57 - Check out Brian Charney Audio in Somerset NJ for high-efficiency, wide band width, single driver speakers.  He makes an honest product, well conceived and executed, at fair prices, IMHO.  I don't have experience with Stein Music or Coincident so I can offer no commentary there.

unless your room is small or your music has limited dynamic range, I think you will find that you will begin to hear an increase in distortion at higher volumes. SET amps begin to produce significant amounts of distortion as they go up in power output. Member Atmasphere has posted extensively on this issue and I have found his opinion on this to be correct in my own system. I think you would like the single driver sound very much at low volumes but as volume and or bass content go up power demands increase exponentially. This was readily apparent with a 300b amp on my 95 dB quasi full range speakers. 

Would a higher power SET using 845 or 6C33C tubes, let's say 40-75 WPC, possibly offer the best of both worlds?  Would I still need to consider single driver designs or 95 dB plus efficiency multi driver loudspeakers?  Thanks again to all.

That much power would work just fine, IMO, unless you have a huge room or want to reproduce concert level sound.