How to flatten a skewplane?

I’m gonna try to explain this correctly, but basically I’m trying to make a pyramid skylight but the base of it is a rectangle with one end of it wider. When I try to lower one point so I could draw the mullions, I’m not sure how to make line up and stay flat and not skewed at that weird angle. I’m really close to doing it but I just don’t know how to interest the lines at the exact point needed. I uploaded pics and the file so you could see what I mean

SKYLIGHT 2.skp (129.6 KB)

I think you just didn’t draw the face quite right. I assume for ease of construction you want a flat face on each side. Since the end curbs are parallel, the gable edges have to be parallel. Redraw the shorter gable? Keep a vertical center line for reference (or use the midpoint inference on the curb). Start drawing the shorter gable edge, hover over the higher gable edge, move the line in the general direction to the peak, until you get a inference highlight, press shift, and align to the center line reference.
(Or just draw both gables edges using the parallel inference until they meet, which will be the center.)

Wow… simple solution that I totally was overthinking… thank you!!