You should be able to find a performance curve graph for your DC. With that you can calculate the static pressure for the pipes and fittings and calculate the FPM air speed in your verticals and horizontals. Each machine should have a CFM requirement and if not there are some general CFM for each machine online. For my system with a 3 HP Jet Canister JCDC-3 collector I ran 6" out of the DC, 90 to the ceiling then around the walls with 4" drops to about 6' from the floor. There I have the gate valve and flex hose to the machine. My ceiling run is about 2' from the wall with a wye turned to the wall then a 90 for the drop. Keeping the wye horizontal keeps chips from falling into the drops.
Michael Dilday
Suffolk, Va.