Exchange Server Test Plan

I am looking for some feedback on an idea i have for testing New Exchange CU's prior to installing them into full production.

so our current Exchange enviroment coniststs of 6 physical server  in a DAG with 3 HA copies and 1 14 day lag of all the mailboxes.

My thought was to spin up 2 VM's with a single database with 4 copies that I can use to install new CU's on and move prodcution users to and from. I know that with this plan, our Prod AD would have its schema updated as a result each time the Exchange team changes the schema. 

previously if i tested a cu it went in my personal test lab but i can do the same level of testing as production users can.

 Thoughts and feeback welcome.