The Yellow and Red belt designs align 100% which, if the devs incorporate my suggestion, would allow for an immediate upgrade by simply placing the 2nd blue print on top of the 1st.
The Yellow/Red belt blueprints can easily be reversed so the materials exit on the opposite side by simply reversing the center lane. For the short Blue Belt design, I've made one each way.
The long one can only insert materials from the rear, although it'd be possible to lineup half the inputs from the front, and half from the rear.... I don't know why you'd want to do that, so I didn't bother making a blueprint for it.
Edited Nov 21, 2018
Blue Belt blueprints shortened to 3 assemblers per belt.