1/2 or 1/4 watt resistors will be fine, I usally use a 1/4 watt 220k resistor and a 250pf capacitor, the resistor smooths out the the volume curve of the pot and the capacitor by-passes the treble frequency around the resistor, I always use a parallel circuit, I have seen the series circuit on the Kinman pick-up website, but have never tried it out, you may want to try different capacitor values, .001 MF sounds like a bit much to me, if you try it and the treble seems to increase, you'll knows it's too much, and try a smaller value. Have you tried changing the tone pot values, or 1Meg Ohm volume pots? I love fooling with this kind of stuff, have fun.........