What matters to your pickups is the total load they see. This includes the cable (which has capacitance), the input impedance of your amp, and your pots. Changing any of those things makes an audible difference.
With a passive guitar (i.e. no buffer on board), the biggest bang for the buck change is usually your cable. Using a low capacitance cable will allow more high end to reach the amp, so you get more highs. (If you're going for a sparkly Strat thing, that's what you want.) Likewise, using a cable with more capacitance will roll-off the top end a lot more and shift things toward the midrange. (More ideal for gainy sounds.)
For pots, you have to calculate the resistance of two pots together (1/total = 1/R1 + 1/R2). If you have two 500k pots, the pickups see 250k. Two 250k pots, the pickups see 125k. More total resistance affects the resonant peak of the circuit, giving you a larger peak in the higher end. To our ears, that seems brighter.
The Super Sport already has a 500k volume and a 500k tone pot, so 250k total. The Axis only has the one 500k pot. Bridge differences aside, the Axis will seem brighter than the Super Sport.
So- you want to brighten up the Super Sport? Try unsoldering one lug from the tone pot (effectively removing it). You want to darken the Axis? Rather than add a tone pot, you can wire a 500k resister between the outside lugs of the volume pot (it'll do the same thing). If you want to experiment for fun, run some alligator clips to the outside lugs of the volume pot and try a few different resistors.
This assumes the tone pot is all the way up (maximum resistance), where the capacitor has no effect. As you turn down the pot, the main effect is to reduce the resistance of the pot, affecting the overall resistance and darkening the signal. As you get towards halfway down, the capacitor starts to come into play.
There's obviously more to it, notably the effect of pickup inductance which determine the window of frequencies they pass. Another thing you can do is wire an inductor in parallel (Bill Lawrence sells a neat one), that you can wire up to effectively reduce the inductance of the pickups, and take out the mids.
Hope that helps.
