No can do. That would be sending full signal to the front end of the Marshall and that would be a mess. If you don't have an FX loop on the Marshall, you would have to just A/B the amps. The way it is set up would be the equivalent of having a power amp of some sort there instead of the head. One reason I like using the head, other than sounding great, is that it gives me a quick alternative during a gig in case of failure.
As a matter of fact. I change knobs on a lot of my amps and generally put a different one on the master. All those knobs on that Marshall, and all my old Marshalls come from Antique Supply. When I change them, or some of the amps with chicken head knobs, I usually replace the master, or masters with different color ones, just to make it easy to grab and go. Bogner Ubers and XTC's are another example. I like those ADA and Stovetop knobs though on Marshall's. Of the 6 or so Marshall's I have here, none have the stock knobs on them.
Different knobs do make the amp sound better. Tone is in the knobs
Yeah, it owns Master of Puppets! We just went through it yesterday at practice. It's been on our setlist for some time now. It's a lot of work for a single guitarist band too.
I've got to fly to Singapore tonight, but will see if I can get time to record the intro and a bit of the galloping real quick before I leave.