DB's may be his own formula. I am not an EE, but I don't think the physical size of the resistor matters in a guitar circuit. Even the lowest voltage resistors and caps can handle the voltage from passive pickups. An EE did tell me once that a ceramic cap is better in a tone bleed circuit, but I don't remember the exact reason. That doesn't seem to keep the SM folks for offering you a giant orange cap for an additional $5.

Most tone bleeds put a resistor in parallel (although my old G&L had just a ceramic cap--no resistor). This will affect the taper of the pot a bit. Putting the resistor in series with the cap tends to affect the taper of the pot less, but also tends (if I am reading correctly) to bleed a bit of the low end as well as the highs. Doing it the DB way (part series, part parallel) splits the difference a bit.

All sorts of other things can affect your tone. Where you have the tone pot, how long your cable is, etc. For my money, the TD approach makes the best sense. And speaking of $, I also appreciate that he and PB have kept it very affordable.