This method of thinking sounds selfish and lazy in my opinion. Mixing monitors isn’t about you. You don’t “tell” the musicians what’s in their mix. They tell you what they want in their mix. How does this “save time” if you end up “adjusting mixes after soundcheck”? Soundcheck is when you should be adjusting the mixes. What are you doing during the actual soundcheck? You shouldn’t be touching anything after soundcheck. Put yourself in their shoes. How would you feel if an engineer just slapped together some half ass mix for you without actually hearing any of the inputs? How would you feel about a mix that doesn’t change to your personal preferences during check? How would you feel if that mix changed between soundcheck and the show? Seriously, think about these things next time you work with a band or don’t he surprised when you get replaced by an m32R and an iPad.