Oops, sorry. What question asked here has been answered?
A treble bleed of any type is a "compensation" device. It attempts to compensate for the loss of treble (predominately, although some will say "tone" instead of treble) as the volume control is turned down.
A low value volume pot, such as a 250K, really doesn't need compensation. A 500K and higher volume pot usually does.
Why? Because of the increase in output impedance of pickups over the years.
Now I know you have heard that a 500K or a 1M pot will sound brighter than a 250K. If the output impedance of a pickup is high enough, then that statement will certainly be true. The higher value pots will present less of a load on the pickups (in parallel with the amp or first footpedal's input impedance). The less the load, the higher the resonant peak of the pickup.
This is not rocket surgery.
But the problem will present itself once that volume control is turned down from the "10" setting that helps provide that lower load brightness. The resistance between the "10" or full on lug and the center or output lug will be placed in series (along with the pickup's output impedance) with a parallel impedance made up of the cable capacitance, the resistance of the volume pot from the center lug to ground in parallel with the input impedance of whatever amp or device you are feeding. The higher the value of the volume control pot, the greater the effect - and the effect is the reduction of high frequencies.
Enter the "treble bleed". (If this same circuit was inside an amp it would be called "bright" and usually wired to a switch). The intent is to provide a higher amount of treble frequencies to offset the treble loss due to the series impedance and cable capacitance.
This is the basic problem. How much to provide and how much to offset.
And since we are talking about passive circuits, change any one component and you will have a different problem. As an example, change your cable to a lower or higher capacitance one and your sound will either be brighter or darker.
Treble bleeds were thoroughly explored during the 1970s. Resistors were added to the treble bleed cap either in parallel or series. Resistors, no matter how they were added, really didn't help, at least not in an economic sense.
Adding a resistor in parallel reduced the depth of the cut, but it allowed more lower frequencies to be bypassed around the volume control. This was no different than the effect obtained by increasing the value of the cap without a resistor.
Adding a resistor in series reduced the "boost" effect to a higher frequency which would have been expected by the cap. This was no difference than the effect obtained by decreasing the value of the cap without a resistor.
So the bottom line - adjust the value of the treble bleed cap, if you choose to use one - to either compensate for the treble loss or augment it.
But in passive circuits, you need to consider the whole circuit, not just a single value... regardless if you want to use resistors or not.