Why wouldn't you just add the Jose Master? Then you have two types of master to mix... From the Metroamp board:
"I think the best overall way to achieve these guy's sound, is to do Rockstah's 2203 mod. Basically a plexi that gives up the section of v1 that was used for the low input, and now uses it to instigate 'overdrive', by means of a potentiometer. This is basically a 2203 Master Volume amp now. The real cool thing is adding a ppimv to it. This uses v3, and also uses a pot. You dime both the regular volume [Gain], and the Master volume,but the ppimv, now controls the 'loudness'. It's like an attenuator sorta. You now have that "not enough gain, sorta 70's hard rock sound" with the 2203 style MV, along with the distorting power tube type vibe of the ppimv when the amp volume is cranked. Like a 'double shot' of gain, at very low volumes. Check out Rockstah's thread "2203 mod", I think its called, in the EVH topics."
Steve