Since live view will not be available till June, how about evaluating focus mask:
Shots with a technical camera that has the ability to fine-tune focus, like an arca, alpa/w HPF rings, or any other available system. Focus in and out from actual focus plane in small increments. Check how well focus mask follows visually on the display.
Point being can focus mask be used to critically evaluate focus? Does it behave just like C1 or are there any distinct differences?