Re: very stupid question regarding using overdrive pedals as a boost..
Are you wanting to add OD to a sound you already like = BOOST, or are you just wanting to add volume to your sound for soloing?
If you are using an OD with just the level turned up, and with the drive and tone turned all the way down, then you are adding an almost clean boost of OD to whatever pedal or preamp you have in front of it. So first you need to find a gain pedal or preamp gain you like. Then use an OD in that type of setup. I said almost clean boost, because most pedals seem to add a slight coloration to the sound. Even an eq pedal. You just have to work with it, unless the pedal has some kind of loop built into it. That would be the only way around the coloration. Can you use two OD pedals? Yep! Just keep in mind that in doing that, your preamp is probably running on clean channel, the first OD is adding your gain/distortion, and the second OD is boosting the first pedal. You can even put an chorus pedal in front and boost it with an OD. You get kind of a screaching heavy metal type of chorus. As far as using an OD as a boost with gain turned up, unless you are on a clean channel with no gain in front. It will work ok. If you try mixing gains you just end up with nothing but trouble, and sounding like crap most of the time. My opinion. People do it though. Just depends what you like.
If you are wanting to just add volume to your sound for soloing, I wouldn't suggest using an OD. I have heard using and EQ set flat with the level turned up works good. I have also heard a Fat Boost works too. I personaly use an identical RM4 module with different solo settings I like, and just turn up the volume knob on the module.
Hope this helps a little. Just remember using an OD in boost setup adds a slight volume increase (not realy enough for soloing in my opinion), a little coloration, and adds overdrive/sustain.