If that 5-way switch can be either a Superswitch or half-Superswitch, then the late, great ChrisK has your back
This one was so well thought of, an actual manufacturer (our member Hembry Guitars) picked it up, as you'll see from the thread.
What's neat about this set-up is that the split-coil options change only at positions 2 and 4 on the 5-way, while positions 1, 3 and 5 always mimic a regular Gibby-style toggle HH setup. So you always have easy access to the regular HH sounds regardless of what SC sounds you have selected with the P/P.
ChrisK's "Industrial Art" drawings can be a bit intimidating, but it does contain every bit of information you need for this scheme. What he had done there is this: The DPDT (which could be a P/P or toggle)switches the guitar between two different "single coil modes". His first drawing shows the wiring, and signal path, for one mode, without the DPDT mode switch shown. The second drawing shows the wire and signal path for the second mode, also without the switch. The third diagram is an overlay of diagram one onto diagram two, thus showing both modes, and adding in the DPDT which switches between the two modes.[/a]