when i think of Entwistle's tone, i think of Sunn, but more of the SS Coliseum's type of tone, cranked thru lots of cabs. roundwound rotos with lots of mids & mid highs.
to me, the tubes ones sound alot fatter and fuller, but they will also growl beautifully when pushed, if you're into that type of thang. i generally like my 2000S best just on the edge before it starts to break up, which means its at a pretty loud volume when its doing that. (feels like about 2/3rd's-3/4th's of an SVT in output).
I agree, the SS Sunns that Entwistle used is probably what he's most known for, and it's not really representative of the tone of the 200S/2000S.
The transistor amps have substantially less warmth and depth, are a little less "hi-fi" than the old tube amps and lack some of that huge bottom end that the Sundholm era Sunn's are known for.
Obviously Entwistles settings and playing have a lot to do with it.
AFAIK Entwistle only used tube Sunn's Nov. '67 - July '68, and this clip from the Fillmore East 4/68 is almost undoubtably using the 60 watt Sunn 100S (guitar version of the 200S, no low or hi boost, mid range "contour" pot instead) and D140F loaded 2X15 200S cabs.
IMO a much better representation of the tube Sunn tone than the transistor Coliseum amps clip.