Okay, so I read up a bit on your mastermind midi controller and the mini amp gizmo for use with my Mesa Boogie Mark V.

I understand that I can program each one of the masterminds 125 presets to turn on almost any combination of the eight mini amp gizmo switches which in turn select any grouping of the 8 features of the Mark V (Channel 1, channel 2, Channel 3, solo, reverb, effects loop, equalizer, and mute). Fine.

But much of my playing is improvisational where I use the Mesa Boogie footswitch to change amp channels, reverb, effects loop, and EQ, on the fly and in no predetermined groupings or order. I understand that if I want to use the mastermind like my Mesa Boogie footswitch, I would do this by placing the mastermind into instant access mode and use any combination of its 5 buttons.

However if the mastermind only has 5 buttons, how do I control the other three Mark V features?

Unfortunately, you're running into the limit set by the number of buttons on the Mastermind. You likely will need a larger controller. We don't have a larger one - yet...

Okay, thanks for the reply. But if I understand the mastermind instructions correctly, it states that while in instant access mode the bank up or bank down buttons can be used to change to another preset, presumably to offer another five control buttons.

While confusing and inconvenient (perhaps too much so), would this allow me to control the other 3 features of the Mark V without disengaging features that I may have engaged in the previous preset?

The IA buttons don't change from preset to preset - they always control the same parameters, regardless of which preset you're on. The on/off status for each IA button can change from preset to preset, but not what each button controls.