Good question. But I'm sure there's a site that maps out every possible configuration.
I was in the SoundControl shop in Glasgow on Thursday buying some bits and bobs for recording a band. And as I was leaving I saw the Burns model hanging up and I thought, "got to try it!" I never have and always chickened out at the thought of it.
I sat with it for about 20 minutes before having to rush for the train home. Moving the switches about was a lot of fun as I heard the differences it made to the sounds the guitar could make. I'm sure I came across the humbucker sound Brian talks about and even the screechier setting for solos. But couldn't hear any more details of the switchings because of the shop ambience, unfortunately.
I also used it with the VBM1 and it was interesting. But since there were 2-3 other guitarists playing through loud amps, I couldn't really latch onto the sound the VBM1 made either. Still, it was fun and I like the feel of the guitar.
Btw, who knows about the Adeson pickups? www.adeson.co.uk
I'm sure I read on a Brian May fan site that these are actually excellent. And a good price, too!