I'm not sure the OP knows what the problem he wants solving is. But there are only two variables. One is the sound he's producing from the processor and the second is what's going out front - ignoring for the moment what he can hear in the in ear monitors. If he follows my advice he can solve the problem by getting his sound right in the processor and then with a long lead (i've done this for years) listening to the mix going out front and telling the sound man what he wants changing on the sound going out if it's possible. He might have to live with the dud monitor mix but at least he knows he sounds good 'out front'.

I think that's all there is to it - and it will solve the problem without him providing any more information. Interesting to hear what happens if he does what i suggest.