>crank the 248 all the way up...
Personally, I completely disagree with this suggestion when the m248 is involved. I have quite a bit of experience w/ the m248 and m148 paired w/ an AD500e and with the modSBM-1. In either case, I much prefer to run as low of a gain setting on the 248 as possible. Unlike the Grace pres, the 248 does not sound its best at high gain settings. It becomes overly bright, and often harsh in the high end when you crank it up. When running the 248 w/ my Apogee, I crank the Apogee all the way up, and apply as as little gain as necessary with the 248. Personally I would shoot for a calibration that allows you to achieve 0db on the M1 w/ 1/4 to 1/2 full gain on the 248 at concert levels. Ideally, I'd shoot for more like 1/4 full as opposed to 1/2.
-mitch