So I got around to wiring it up today. It seems to work best at higher volumes. It feels like about a 40% drop in volume, which guess is to do with the way power and volume interact. 75% less power doesn't equate to 75% less volume. For some reason, this build breaks up late, and at the moment I'm running a 12AY7 in V1 and a 5751 in V2, so cutting the power still doesn't get into bedroom filth. I'll report back with a tube swap later. It it worth it? Maybe. Time will tell.