I’m not sure what the dispersion angle is of the 3-6 cell models. I’m waiting to hear back from Roger about that.
Take a close look at the first video in the other thread. As Roger is explaining how the membrane is attached, he appears to be using a 3C model, most likely a 745. Note that the center cell appears face on while the two adjacent cells look like they are angled at about 22.5 degrees to give the 45-degree curve.
I guess the 4-6 cell variants would have cell angles that vary to maintain the 45-degree total.