Peter, you know the ONLY thing that I can think of would be a stereo Herbert to improve this setup.
I know, I know, I'll just need to buy another Herbert
Truly, I have searched long and hard for an amp that would provide great tube distortion straight out of the box, and I have finally ended my search here.
It's amazing all the tones I can get out of this amp, and the easy interface and MIDI controllability of functionality is an awesome bonus.
You have succeeded where all else have failed IMO.