mjw25a,
FW_SIT3 2nd harmonic is significantly dominant over the rest of the higher order harmonics. I do not believe that any more dominance of the 2nd would add any benefit. I have studied this quite a bit...on the bench with a proper audio analyzer and most importantly side by side comparison with other vfet amps.
I can't wait for your impressions of the new amp. Based on the few photos I see on the net it looks like a nice project and of good quality too.
Please share your impressions.