so the idea with all tube amps is that you run them as hot as possible to get all the pre amp and power tubes saturated to get "that tube" sound. This means cranking the volume !!!

So, if you can do this then yep get a 100 W monster.

The cab / speakers will also make a difference as will the type of tubes you are running . You might want to speak to Bob over at Eurotubes.com.

I have two levels of power attenuation to stop the law from shutting me down. One is a built in feature of the TSL, the other is a Marshall power-break (PB100) which sits between the amp and the cab. This has an incremental attenuation calibrated in db and although it sucks some tone, well it enables me to turn my amp above 1.