Colin Hester suggested that I should post Earle Weston's Design here.

I will have to get a move on with the rest of the hardware.

Power Output Ultralinear Pentode Mode.
1. 6L6GC 9.5 watts
2. KT66 9.0 watts
3. EL34 12 watts
4. KT88 14 watts

Power Output Triode Mode.
1. 6L6GC 4.3watts
2. KT66 4.6 watts
3. EL34 8.7 watts
4. KT88 8.8 watts

Frequency response............................+/-3dB 20Hz-45kHz
Separation....................................…. >70dB
Signal to Noise.............………..........>85dB
Distortion.................…....................