"In the range of 40-100 degrees F, the ratio stays at 83%. That was the point of my post. In the woodworker's range of duct size and flow rates, the 83% value always works."
Well, if you've done the calcs, I'll take your word for it. Getting out my grad school fluid dynamics book is not my idea of a fun evening. ;-)
But, there are other assumptions here, one of which is that an idealized laminar radial flow profile is the case. The presence of pipe bends, junctions, blast gates, the use of corrogated pipe, and most importantly, the presence of dust and chips in the fluid stream is likely to yield substantial deviations to the laminar flow assumption, so a chart would be perhaps a decent measure of relative differences between pipe sizes, but iffy as far as the validity of the absolute numbers.
Besides, why would this matter? I'm assuming that someone that's setting up a dust collection system has only a few choices of horsepower/single vs. multiple stage/amperage draw, and most of the available collectors from the various manufacturers within a given class (for example, single stage 1-1/2 hp) are going to be darn close. What I'd think someone doing this would be considerably more interested in is how well their blast gates seal, minimizing pipe run length, and avoiding unnecessary bends in the network. Under those circumstances, I'd think using a velocity meter to measure relative differences instead of trying to calculate absolute cfm would be considerably simpler.