I want to use one pot as master volume and the tone pot as "impedance pot" with the qfilter, because I never use tone pot in guitars (don't like cut high frecuencies).

Edited... few hours later...

Ok, I have conected the pot like BL schematic and it works. I feel turning down the pot less "gain" in distortion. I suppose this is what it must happen but it seems to me that "reduction" is small. I mean if the pot is turned to 10 and the gain is maximun, turning to 0 I get +-40% of reduction.
Is correct? Qfilter works like this?

Thanx