The Function and Abstract of Tone Pots and Capacitors in General:
When a tone pot is turned all the way up, ie. in the full treble position, ...the pot's full resistance value stands between the signal and the capacitor that feeds to ground; So the greater the pot value, the less signal can get to and bleed through the capacitor to ground. So we can see that a 250K pot would allow more signal to bleed to ground through the capacitor than a 1Meg pot that would block almost all signal quite well; And so a 250K pot would give a guitar a somewhat bassier tone for a particular capacitor value than a 1Meg pot would, when the pots are turned all the way up to full resistance. On this guitar you will notice that the volume pot at 1Meg is used to accomplish the same purpose, while the volume pot will be much more sensitive to changes than a 250K or 500K pot; Although bleed over through a cap can occur as the volume is turned down to lower volume settings; Simply a matter of engineering design preference, usually with the advice of knowledgeable Guitarists in the engineering Research and Development department.
But when a tone pot is turned down, it's resistance is reduced and allows more of the signal to get to and go through the capacitor to ground, and the frequencies that get through the capacitor are determined by the capacitor's value.
When the pot is turned all the way down there is no pot resistance, so the only thing that stops all the signal from going to ground like a volume pot is the capacitor that only allows some of the frequency range to go to ground. So the capacitor alone determines the tone passed to ground with the tone pot turned all the way down. The chart on the right shows the range of frequencies that are blocked and that are allowed to pass depending upon a capacitor's value. (uF = microfarad).
Another condiseration is that it takes power (voltage) to push signal across a capacitor; And the higher the frequency, the less power it takes; So as a tone pot is turned down from full on, it commensurately increases the voltage across the capacitor, with the highest frequencies crossing the capacitor first at lower voltage, while more and lower frequencies will cross the capcitor as the voltage is increased by the tone pot / resistance being turned down, UNTIL the frequencies reach the minimum crossover frequency of the capacitor's value; And that's why the tone pot gets bassier the more you turn it down thus turning up the voltage entering the capacitor.
RECAP: The most common tone pot capacitors values are between .050 and .020 uF. The resistance value of a tone pot will effect tone at the full on / full treble position, and how fast the tone will roll off across the bassier tone range when the knob is turned down. The capacitor alone will determine the tone with the pot turned all the way down. Notice that this guitar's tone caps values (.047 and .020 uF) fall near the extremes of the normal range.
In the chart below the capacitor value columns and frequency range sections are samples of the both, when in actuality both capacitor values and frequencies are spread across a spectrum of both.