|Personally, I recommend MultiSIM as a
great circuit modeling program. One of my favorite features is the
ability to assign "hot keys" to switches in the circuit. These can
then be controlled in real time from your keyboard to toggle options when
testing the circuit to ensure it works as you had intended.
The following circuits are in MultiSIM. I am not an expert on programs like this, but it is based on PSPICE, so I would imagine these files might work on other, similar circuit modeling software packages. Let me know if you have any success with these on other programs, and I'll share that info.
Notes about modeled circuits
Note that in these models I set the output of the two (or more) "pickups" to different levels. To me, this makes it easy to see whether they are summed (i.e., connected in series) or if you're getting the reciprocal of the sum of their reciprocals (i.e., connecting them in parallel). You can also see if you're getting phase cancellation if they drop. If both "pickups" had the same output level, then reversing the phase of one would result in 100% cancellation or zero output, and this would be indistinguishable from a switching combination that simply grounded out the signal entirely.