Don't buy a CV Max unless you are prepared to go to a bigger main duct and six inch ducts to the machines which have had the ports opened up to match the duct. I used to sell Clearvues and my recommendation is 6" all the way for the 1800 and 235mm main duct for the Max down to 6" for the verticals and somewhere in the centre of the work area an open 6"duct to atmosphere. This pulls air in from the work space including the floating fines and caused a bigger change of air in the work area. The 235 main duct was sized due to local supply conditions, I have no idea of equivalents in the US but around that size works. Getting excited about exact duct sizes etc is unnecessary in a hobby shop, properly designed bell mouth intakes and machine ports is way more critical as these allow the maximum capture ability at the source because once it is in the air the damage is done. Just remember the minimum duct size for any DE should be 6", if the DE can't support that size duct buy one that can.
Chris
Everything I like is either illegal, immoral or fattening