Responses from beavis

Yaqin MC-100B or Cayin A-88T - first tube amp
I hope another forum post is O.K. See reply by Jan Vigne on Ecoustics message board: He makes some real good points about tube amp specifications & reality. 
Audible Illusion L1 / M3A, which tubes ?
Tubes that are quiet with very little microphonics. See: 
Does speaker toe-in affect reflection points?
See: down to Figure 4. 
Retractable room treatment
To what end? It's certainly a cost you'll never recoup if you sell your house. Also if you ever reposition your speakersÂ… Interesting idea but why not consider a special built room by Rives. 
Ear Protection
Ooou! Ooou! Tell the morons in the cars with Ghetto Blaster bass speakers they will lose they're losing low-frequency hearing while listening to bass heavy music. 
Which tweak for new amp: PC or footers?
Listen to amp for several months before considering tweaks. 
Best Diana Krall
The ones where she is NOT backed by an orchestra. 
Office System -- Low Volume Speakers
For low volume work I assume you don't need a lot of bass. Consider the less expensive full-range drivers from Omega loudspeakers. 
Isolation damping for furniture
I've never had that particular vibration problem. What material are the doors made of & how are they attached to cabinet? Can you remove just the doors? 
Assessing room response
Jusr remember, if you like the sound, it doesn't make any difference what other's think. 
Toslink Connection Flakey
Sounds like a bad TOSLINK connector. Is it still under warranty from PS Audio. 
recommended 6922 tubes for a moderate price?
Try the JAN-Phillips 6922. It seems to be a very good value.I bought mine from The Tube Store ( I assume it is available elsewhere, too.You might try your luck on eBay, also. 
How tall should speakers be?
BlindjimIMO, it's driver integration. 
How tall should speakers be?
Some speakers have a critcal vertical listening window. I owned a set of Spica TC-60s ten or so years ago and tweeter response was radically different if you were standing or sitting. The difference was even audible at about +/- 5 degrees. So, yea... 
gain control issue
Are you saying 2.5 on the amp volume control or 2.5 o'clock. Big difference. Especially for us not familiar with amp volume control. Basically, if you're not driving your amp into clipping, you're OK.If bothered, you can always use fixed attenuato...