I'm getting ready to build my first midi rig and would like some advice. As of now, I only have my guitar, amp head, and cabinet. My amp is a Mesa Roadster, which is a 4 channel amp with fx loop. I will most likely use a multi-effects unit in the loop but am considering pedals. I would like to put a Tube Screamer between the guitar and amp, but only be activated when I am using my distortion channels (3&4). I want to keep my footwork to a minimum. So, I need to have a way to switch the Screamer on or off, change the amp channel, and switch the effects in the loop with the press of a single button. What am I going to need to make all this happen?