If it's exactly like in the pdf, you can disconnect the capacitor leg that goes to the volume pot (thus bypassing the tone control completely) and check if you still have the problems with your volume pot. If you do, I would just replace the pot.
Now with the regards to the cap. I don't think it should affect the volume taper, but I'm not 100% positive on that. Anyways, "As the cap gets smaller, the minimum tone knob settings gets less dark." So substituting it with a 1000 times larger cap (as in 0.022µF vs 0.022mF) will make it even more dark when the tone pot is rolled off, effectively making it a "treble on/off switch". But if you always keep it all the way open and never touch it, I wouldn't worry about it too much.