I have the boost level fixed via the inputs page (under Levels).
I have a new MIDI controller (Liquid Foot Pro), and I will be using a Mission expression pedal with it. That pedal will be connected to the Liquid Foot exp. pedal input 1 (and not to the GL or the H8000), and so I will use it to control a variety of parameters in the H8000, but I have not made those assignments yet.I'm sure I'll use it as a volume pedal in some presets.
I was doing some playing tonight, and I used one of my basic "bread and butter" GL routings: Guitar–>Triad pedal (this is a clone of the Korg SDD-3000 delay preamp/boost)–>H8000–>AC30
With my guitar input to the H8000 boosted by about 20 dB internally *plus* the Triad pedal, I found that I pushed the H8000 meters into the red when I hit the strings hard and really dug in, which resulted in some pretty ugly digital "booms" coming out of my amp, even though I cut the output dBs considerably on the outputs page. I'm pretty sure I clipped the signal. So, I went in and cut the input boost to about 10dB, and I didn't seem to have any problems. I may experiment more with running two parallel signal paths: Guitar–>Triad–>AC30 and Guitar–>H8000–>AC30 and compare the results to running in series.
Any tips and suggestions would be appreciated.