You could use the volume pedal "model" if you put it after your gains and filters and set it up just like I was saying up there where heel down would be your normal volume and toe down would be your boost, but you're only going to unity gain, as the other poster said. For what you're looking to do, I think that hitting the front end of your amp with a bit more gain usually gives a better result. BTW, as long as your not doing anything more than boosting, you might want to play with the position of the boost and see where you like it best. I tend to run it just before delay and reverb so that everything else is seeing a normal input level, but you might like a little extra gain bumping up overdrives and distortion. It's worth trying a few different ways.