I just ran into another problem that the 135 solves. Funny how these things happen.
My Omega D5 with color head has the standard length girder, not the XL girder. So I am limited in the max height I can elevate the head to, and thus max enlargement on the baseboard. The 135 will give me the ability to still print 16x20 (if I want to) on the baseboard. The 150 is just at 16x20, but leaves zero room for cropping, and I almost always crop on the enlarger. So it looks like I will be using the 135 on the Omega, and using the 150 on the Durst.
I will check what the light fall off is with the 135, when I get my darkroom constructed. Hopefully it will be tolerable/unnoticeable.