Why not more on 845 SETs?


As a brand-new owner of a Bel Canto SETi40 int amp,(bought used) I was intrigued to see very little in the fora on the subject of 845 SET amps an A'gon. It seems that this provides the best of both worlds -adequate power to drive most moderately sensitive speakers- 40 Class A SET WPC with SET sound. What is the downside to this approach and why don't more of the SET groupies have higher powered amps, giving them much more latitude in speaker selection? I drive 4 ohm 87 db sensitivity Totem 1 Signatures quite adequately with this amp. Is it beacuse of transformer issues, difficulty in finding adequate designs, size or the feeling that this is not a true "SET sound"?
I would like to hear SET-owners' reasons, if possible.
springbok10
1. There is the standard 845 tubes
2. There is the 845B tubes which are supposed to sound better than the standard 845 tubes
3. There is the 845M or metal plate. It seems the production of these may have stopped till modifications are made. Be careful when using these tubes as the current requirements are different and some amps may not be able to handle without modifications. In the Dehavs they have to be biased a whole division lower on the scale.

4. 845 NOS Tubes. They cost a fortune and sound a bit better than the chinese 845s.
As you go from the standard 845 to the 845B to the 845M the sound gets smoother with more detail and texture in the midrange. The presentation gets darker and more relaxed. It is a matter of preference. I would recommend atleast the 845B. I think the 845C is the same as the metal plate. I could be wrong.
That website shows this tube available, but not the 845M, thats why I am asking. My amps will be delivered by the end of the week, and I am a tube junky, so I wanna get set for some fun rolling. Too bad they do not have M's to ship now.

Thanks