How does it sound?  Pretty good.  Very loud, much louder than expected, loud enough for a rehearsal of a 20 piece swing band with full rhythm section and amplified bass, keyboard etc. Distortion gets a bit unmusical at very high volumes, I suspect due to limitations of power supply, maybe lower than spec filament voltages of power valves. But overall very musical, lots of complexity in the high range, lots of thump in the bass and the mids seem to be a bit compressed. I use a Tele with humbuckers. I may reduce the first valve stage cathode bypass cap as you suggest to unmuddy things a little.  The wiring is a bit of a rats nest due to the tiny chassis and quite a few layout compromises and to be honest as I finished connecting the valves I thought that it would be a humming oscillating buzz generator, but to my surprise I think it may be the quietest amp I have built. 

Here is short clip with some blues noodling live and direct from my garage and captured on an iPhone, rhythm track courtesy of Ditto Looper. All amp settings including volume about middle, reverb a bit lower. Neck humbucker.