One configuration that would work with those options is one of the toggle switches giving you neck/neck+bridge/bridge, with the other switch giving you middle on/middle off- it's a setup that telecaster players sometimes use when they add a middle pickup. This gives all the sounds you had before, except middle pickup alone, and also gives you all three, and neck+bridge, which you didn't have before. So you'd start by wiring this diagram for the neck and bridge:
And then adding the middle pickup according to
this description
One more toggle and you can do the Brian May
Red Special wiring-each pickup available in and out of phase for every possible series combination from three pickups
