Our system contains one-sided and multi-sided connectors in a 90, 120 and 135 degree grid. All connectors have a height of 30 mm and their clamp jaws always attach to a 16 mm band (exceptions: Type Z and I).
Connectors with a threaded hole have their threaded hole on the axis intersection.
Between the edge of a panel and the axial intersection there is a space of 8 mm on each side. Consequently, the dimension between the axes of a connector is 16 mm. So, for example, if you plan to set up a construction in 1000 mm sections, each panel on each side should have a length of 992 mm.

(The shelves are to be put on the inner side of the clamp jaw and are a bit smaller than the (clear) dimension.)