I think we covered some of this in PMs, but want to put it out here for others to see if someone experiences trouble down the road:
[1] Make sure you're not overloading the M1's analog inputs. Basically, run the MixPre levels low and set the M1 Rec Level on the high side. You also may consider running stereo-mini out of the MixPre instead of XLRs, I believe the stereo-mini provides a signal that isn't as hot as the XLRs.
[2] In what configuration are you running the MK4s? Consider closing the included angle, it should help minimize crowd noise and bad room acoustics. For example, if you're running ORTF (17cm, 110º), try switching to DIN (20cm, 90º) or even a non-standard stereo config (20cm, 70º). If you're using the Schoeps ORTF bar, you'll need to pick up some different mic mounting options. FWIW, I like the DIN Kwonbars available at
Cascade Media.
[3] Location, location, location! Once you have your gear, the single best thing you can do to get better recordings in crappy venues is to set up relatively close to the sound source. If I'm unfamiliar with the venue, I usually try to set up so my location creates an equilateral triangle with the stacks. While it may not always be the best spot, it's a good starting point.