Sequencing the mull depth edit for a tall window stack

[GeneDavis]

Try it and see what ya gotta do.  Or am I doing it wrong. 
 

Place a fixed window in a tall wall, 2' w x 2'2" h.  You're gonna mull and stack and the ribbon mull parts need 1/2" spacing.

 

So copy and paste one adjacent, spaced 1/2 between.  Mull.

 

Your big stack is 5 high, so copy/space up 24-1/2" up to make your 2x5 stack.  Mull as req'd to make one big unit

 

In 3D camera, look close at the mull joints.

 

They're all 1/2" proud.  You want them all flush like the real-world end result.

 

Now go about making them all flush, and report.