Well, what I would do is this: swap out both pots for push-pull pots. Use one to cut the coil(s) of the humbucker(s) and the other as a series-parallel switch. That would give you a lot of tonal options. DVM has the
wiring instructions for your perusal. Check out "Basic Coil Cut Wiring" and "'Megabucker' Series Wiring" on that page. Depending on the humbucker(s) you should be able to have the middle position be hum-canceling with the humbucker(s) in single coil mode.
Then you'd have these options:
Bridge only (single coil or humbucker)
Neck only (single coil or humbucker--assuming you swap out the neck pickup)
Middle in single coil mode (series or parallel)
Middle in humbucker mode (series or parallel)
Suddenly your guitar goes from three tones to eight. Not at all bad.