I wouldn’t worry too much about going 5” from the DC to the separator, but keep the lin short between the two. The bigger concern is keeping the amount of flex hose to a bare minimum because it kills performance. I recently did a test where I measured CFM on a port with mostly PVC and a couple feet of flext at the end, and then the same length duct but this time 14 ft of flex at the end, and the CFM dropped from 850 to 550. There were other minor variables so it wasn’t a purely scientific test, but the difference was dramatic. The “real world” result was that 850 CFM kept up with my planer just fine, but 550 CFM didn’t cut it. I would consider building the Thein baffle into the DC itself, and using a single 10’ x 4” flex hose and I think that DC will keep up with any machine in your shop under most conditions.
-- PaulMayer, http://www.vernswoodgoods.com
