If you talk to pro guitarists who do lots of cover work - stepping in to bands or sessions and having to play many styles, they tend to do two things. Very often they will set their amp up with a dirty and a clean channel - each with separate EQ, and that gives them two basic sounds, then they use multi-effects and/or individual pedals to switch between the characteristic sounds of many different styles and players. Most complicated is probably covering for a function band - look at the set list and it is Sultans of Swing, next to Smoke on the Water, followed by the shadows, then a few 60s songs, then Snow Patrol. Throw in the occasional Hendrix song or Abba, and finish on Queen. That is an awful lot of EQ, gain, distortion and effects changes. So changing so many settings is a task and a half. Most can use what is on the floor and a general setting, or maybe two on the amp. Things like kemper amps can make this kind of thing easier to do, and sometimes the changes can be programmed into qlab or a DAW and can change settings for them if there is no real time. Qlab driving video screens that are triggering lighting and audio cues is quite normal for some things. It's quite fun watching some of the production shows I get involved with. The guitarist is playing with the band, off-stage and at a certain point, (as he has a radio pack) he legs it down a flight of stairs, somebody shoves a wig on his head and he bursts out on stage to do Bohemian Rhapsody for 30 seconds, then runs back up the stairs straight into a Chic number. His guitar changes are done by the computer - he touches nothing! Works great till a cable falls out.
