Does anyone know how to modify the Bass Grunge's "zip"(tone) control to get more bite or treble

At the moment, i running a DOD Bass Overdrive as an almost clean active/pick-style/trebly sound into the grunge for just a small amount of drive to get a kind of Overkill/Anthrax-like bass tone, ive tweaked the Grunge almost the same as both pedals together, but even with the tone all the way up and gain almost gone, it doesn't have the same attack or clarity as the two in combination. So at the moment I'm using the Overdrive for it's tone and Grunge for it's Distortion, but would like to get the sound of both using only the Grunge. If it's of any help, my setting(sample called "meaty treat" in manual) for FX91 Bass O.D. are LEVEL 1:30, BLEND 3:30, TONE noon to maxed out(depending on bass), DRIVE 10:30, the FX92 Bass Grunge is LEVEL 2:00, BLEND 10:00, TONE 8:30, DRIVE 7:30(or just on), the closest I've gotten to this sound with Grunge by it self is LEVEL between3:00 and maxed out, BLEND 9:30, TONE maxed out, DRIVE 7:30(or just on) so im not far off, but could use more treble. Im stationed in Hawaii, so repair guys are few and far between, i contacted one local guy who fixes amps who said it could be simple as replacing the tone pot, but I've read elsewhere to do this as a last resort and to swap caps and resistors first. I'm no electrician, ive been playing for 20 years but have never soldered anything, and am not gonna start with my pedals, and i don't want someone else tinkering without having as much info as i can, any ideas, anybody??
