OK, this sounds good, too. So this low-cut only affects the neck pickup? If so, how is it integrated into the rest of the wiring?
The circuit you drew is basially a pot and a cap, right? but is it the existing tone pot, or a separate one?
It goes in series with what you want to be affected, in your case the neck hot would go come in on the left, the right would got to the switch.
One advantage of this over the bridge (hi cut) tone is the bass cut won't affect the bridge pup in the bridge+neck setting like the bridge tone would.
Yep, just a pot and cap, A 1M pot is best, smaller values (500k, 250k) aren't as effective. A 0.001uf cap is good, I always tune it to taste to match the particular guitar.
separate pot to the existing tone, I assume the guitar isn't complete? so you have the option to have more that two pots?
I've only done it to teles who's owners complain of a muddy neck pup, all have been single bridge and humbucker neck, all have replaced or rewired the stock tone pot. I use the stock 250k pot if does the trick, if it doesn't have enough range for a particularly muddy pup i'll put in a 1M
Of course, whether the bass cut will be any use to you depends on your ears, your pups and your guitar.