This is my 3rd revision of portable regulator stand, to be tack welded from 1/4 inch plate steel, carefully shaped by angle grinder, for my Harbor Freight Tools industrial air pressure regulator. Holes are 3/8 inch, to be drilled using cobalt steel drill bits on a properly geared drill press - of course don't forget the cutting fluid.
All three outputs of my regulator are now tied into a single 1/2 inch Goodyear hose using MettleAir 1/2" hose barb T's from Amazon.com and Oetiker clamps as per the training video from the Dixon Valve and Coupling youtube channel. This should provide me with approximately 40 cfm at 87 psi for my new air pick. Skipping over a lot of research here.
Note, a simplified schematic of the regulator is shown - not including diaphragm housing, pressure gauge, etc. - for the purpose of my estimating where my 1/2 inch Goodyear hose may fall. This placeholder for my regulator is approximate and that's okay because I designed what seems like plenty of extra room to aid in draining water and checking the coalescer.