Cyclone size as a rough approximation of Thien baffle dimensions

[banderton]

I thought this brochure of cyclone dimensions for various sized models was pretty informative in terms of sizing dust separator barrels, inlet sizes, cfm, and motor sizes.  I'd like to know what folks think about me using these as sort of rule of thumb guidelines for how to size the drum/baffle, inlets, etc.

Kind of putting together the pieces that I thought was useful is summarized in the table below

Diameter-------cfm------motor HP-----inlet size
12 inch--------300-500----3/4 HP-----4 inch
16 inch-------800-1200---2 HP--------6 inch
20 inch------1200-2000---3 HP-------8 inch
24 inch------2000-3500---7.5HP-----10 inch

I bring this up because I've got one of these Cincinnati Fan model 200s 2HP 1100 cfm barrel top collectors on a 55 gallon drum with 6" inlet.  I was thinking about adding a side inlet and a baffle to the barrel so it would have a 24" diameter inside the barrel for the separation chamber.  I am thinking now, based on the table above, I'd be better off making a 16" diameter tophat with a side inlet so I get the higher rotational speeds at the cfm range I'm at.  I'm thinking that for a given inlet airspeed a 16" drum is 50% higher rotation rate than a 24" drum, just based on the distance around, hence the need to match the vessel diameter to the CFM coming in.

Maybe as more of a direct question, is there a target rotation rate we are trying to achieve, which could be arrived at via linear airspeed at the inlet and drum circumference?