This is a 12x constructor setup, with underfloor belting. Complete with power, lighting and starter grid walk traversing the centers of the constructor floors, of which there are two.

This isn't a really tight setup, as I dont like cramming things in there and its built using a max conveyor of 270pm. It has a bottom input and a top output, with a second layer output to be able to either stack vertically or next to each other.

You can do what you like about the grid walk area, or follow the example in the pics where I just connect both floors and the ground with stairs. This is my first ever blueprint I thought was good enough to post here, hope you like it.