You've edge mounted the output jack, right? So, you have the large pickup selector hole and now 4 + 1 pot holes?
You could use push/pull volume and tone pairs for each pickup which would allow you to have series/parallel/outer coil/inner coil switching. That would give you a lot of variation. Or, if you wanted to keep it a little more simple, you should be able to switch both pickups with just one of the volume/tone pairs as push/pulls (standard pots for the other pair). That is, it would switch both pickups from series to parallel to outer coils to inner coils at the same time. For the remaining hole, if you can get a 3-pos switch with enough poles (have to work out how many), you could have parallel (standard)/series switching between the pickups for when they are both on and the 3rd position could be the kill (all off). Or, alternately, the switch could be in/out phase and kill or something like that.
Or, volume pot and series/single coil/parallel mini-switch for each pickup and then a master tone. Simple, but still a lot of options.
You could even maybe do a varitone type setup or something similar, but rotary switches won't always fit through an f-hole so that may not be possible.
What do your pickups sound like when coil split or in parallel? It may pay to research and see if you can get some sound samples, as it may not be worth having all the switching options if they are not going to provide the type of sound you're looking for.