angled gable windows - blocking

[05uurx]

I'm working on a log home for a customer and its got this big gable wall, cathedral ceiling, and large angled windows. I'm having trouble mulling 2 angled windows together cleanly...see attached pictures, the full elevation shot is showing the windows seperated, and the close-up is showing them blocked.

I'm thinking the problem is the size of the windows themselves, i've tried to solve it geometrically but i've not yet been able to get the exterior trim to align properly once the 2 windows are blocked together.

any tips or tricks to make this work? or am i going to have to clean this up in CAD?