Sorry...Are you gigging or anticipate gigging in any Medium to Large Venues anytime soon?
If the answer is no, why do you need such power? The Blues Junior will get er done and keep the neighbors off your (maybe)back.
Or if they have really good hearing, keep your amp and buy a Vox ($139,95 or so) DA-5. It will get you a lot of tones with a variable selector for wattage output and a place for headphones.
Good Luck
don't bother with the power attenuator, just make a small box with a 100k volume pot and put it through the effect loop IN-OUT, or a volume pedal for that matter would do fine, leave the pre volume at 3-4 where you get max headroom and lower it through the effect loop volume "box" or pedal... or you can buy one for 15-20$ on e-bay if you dont want to make one... R.
