Does anyone have the gain specs for the MC250 and the MC225.....with the gain pots turned all the way up? Thanks!

Bear in mind they may have the same input sensitivity for rated output, but one is rated twice as much power as the other so the gains will be different. So, going with the 0.5V given above, the MC225 should be about 29dB gain wide open while the MC250 should be about 32dB gain wide open.

Find the voltage at the rated power and load then factor that against the input sensitivity for rated power at that load. For example I'll use the MC250. Rated power @ 8 ohms is 50 watts. 50 watts @ 8 ohms means 20 volts. Input sensitivity for rated output is 0.5 volt. dB (voltage) gain = 20log(20/0.5) = 32dB.