I have a Carvin semi with a Carvin C22B bridge pickup. That's a fairly hot pickup with a touch of the cocked-wah sound in the mids. I have it set up with the slug coil nearest the bridge, so when I flipped the splitter switch it grounds the junction between the coils leaving the slug coil active. That left it too-thin, too-bright, with too much of a volume drop. So I inserted a resistor in the splitter ground path that leaves the screw coil in-circuit but reduced in output. After playing around with different values I decided on a 10k for the best balance between single coil-y clarity and guts enough for some Tele-like drive. Now I'm considering a 3-position switch to add a just-slightly-thinned humbucker sound using a bigger resistor, like around 51k. It's a different effect than coils in parallel and doesn't need a different switch.