Not leaving room to turn those upper knobs but mostly-
IV and IIC+ modes both a little disappointing. When I went to extreme I was expecting fizzy, hissing, loud crap but finally-that's what my old Mark IV sounded like. This is with using a modded sd-1 as a boost also. Very powerful and tight articulation. 7th and 8th strings are focused and clear (even tuned a step down).
The IV and IIC+ modes will be nice to some people but extreme doesn't sound "extreme" to me. I think it's the best mode on ch 3. I can use it for rhythm and leads.
On the plus side-solo boost replaces a volume pedal, cleans are great. Will keep tweaking with 10 band e.q., bbe, etc.