Fiber cement facade + aluminum-clad windows how to do?

[frityreldarn]

I am considering re-cladding the entire house with a fiber cement facade.
Horizontal tongue-and-groove "boards."
Then I'll replace the windows at the same time, but I'm not sure how far out the window "should" be, both structurally and aesthetically.

How do you connect to the window?
Do you cut straight and let the facade extend 10 mm over, or?
Seal, not seal?

I know the suppliers have metal solutions, but I don't like the look.

 

[sturnus]

Do you cut straight off and let the facade dictate over 10 mm or?

It probably won't. The boards must lie on the wooden grate. So the window would have to be extended beyond the wall structure to be flush with the cement boards. The only sensible alternative is flashing which will prevent rainwater from leaking behind the boards