Assuming I have a blend pot which has both tracks at half their travel in the middle dent (unlike the stewmac pan pot), would it possible to put part of the output of a coil in series with another coil, and the other part of the output in parallel with said coil. With my limited understanding, I can't quite figure out if its even possible, let alone how its done.
I had a thought, since a blend pot and a DPDT switch both have 6 terminals, could I wire it up like a Series/Parallel switch list (like the one referred to as as D here:
I'm not sure what you mean by "as as D here", but the first drawing in the link functions as an analog (variable) equivalent of a DPDT ON-ON-ON or DPDT Center ON or SP3T switch (all three descriptions are the same thing, it's a three position toggle switch with two sets of poles).
It's called the "Blend Pot Coil Split" and I designed it to do exactly this. If you read the text on said drawing, you will see how this works.
Assuming I have a blend pot which has both tracks at half their travel in the middle dent (unlike the stewmac pan pot), would it possible to put part of the output of a coil in series with another coil, and the other part of the output in parallel with said coil.
It doesn't quite do this since this is not possible without a tapped connection on the coil.
While blend pots are at half of their travel in the center detent position, they are not at half value unless they are linear pots (such as the Fender active bass blend pots available thru authorized service centers).
By the way, the StewMac pot has both sides at full to one side of the wiper and both sides at 0 Ohms to the other side of the wiper (both sides are "at full on" [their words] in the center). this is what you want for blend-able series/single coil/parallel.
"Normal" blend pots are at equal power (as on a stereo mixer panel, each side is really -3dB) and are not the best for this as noted on said design drawing.