Right, try this and see what you think - it's top of my head stuff in relation to what I use on my JCM900... but:
(Working on the old o'clock method)
Bass: 11 o'clock
Middle: 5 o'clock
Treble: 1 o'clock
Presence:3 o'clock
Gain:12 o'clock
Go from there and see how it sounds, obviously it depends heavily on the sort of guitar/pickups you're using but for me, this works a treat. My main guitar is a Fernandes Ravelle with a Seymour Duncan JB in the middle - a pickup with his the EQ slid up in favour of the high end while I prefer the mids myself. GUITAR IS ALL ABOUT THE MIDS!! So, lower the treble a bit, drop the bass and crank those mids!
Give it a whirl and see what you think. It might rock, it might suck.