You know how splitting a hb for single coil tone often leaves one with a weak, thin, tone, esp if using a lower impedance pup. I am experimenting with using a pot to blend in the tone from the unused half of the hb and it seems to work like a fat boost to reinforce the remaining single. Full on returns the pup to full hb mode. The loading effect remains undetermined, but not much. Instead of using a switch to ground the point at which the 2 coils join, insert a pot as a variable (series) resistor to ground. This is to allow the unused coil to contribute some signal. There may be a better way (?) and I am using a 230k pot that was already in the guitar and the sweep of tht is a bit radical, but the concept appears valid. BTW, it also is effective in altering the tone from series wired pups as the single coil effect brightens the pairing. Too many options?