DavidNJ, everytime dust collection threads come up somebody almost always tries to direct you to Bill Pentz. I have read and reread his website and am amazed everytime I do. It's alot to read but he has the best (IMHO) advice on true "dust collection" not just chip collection.
Try to use this as a guide for what you need:
http://billpentz.com/woodworking/cyclone/index.cfm
Try to use this as a guide for what you need:
http://billpentz.com/woodworking/cyclone/index.cfm