Used 12 by 8 by 2 - yes easy fit. Note I used a different power transformer since I had it, by Edcor, I think it was a bit bigger than the Hammond. Really happy with the sound

Built the compactron tube amp from Skunkie as well as her 6BM8 - both sound great - compactrons are easy to find (got 5 at a radio show for $2 each - no one wants compactrons these days!) Is the 6CL6 a drop in for the Zen design instead of EL84?

I built the version of this shown on the website with their PCB on a wooden board. It does sound nice with EL84 and 6DJ8 but I have to say I prefer the Skunkie 6BM8 sound, though the differences are subtle. Love the way you built this - looks really nice.