J. Phil Thien's Projects

I am currently ready to finish my HF DC cart, new baffle lid and to start ducting my shop.  The cart has the blower flipped and a short straight shot the the baffle.  That will be a 5 inch diameter connection.  I would like to duct the dc to the majority of my tools, planer, jointer, band saw.  These tools will be inline over about 20'-0".  My table saw will be connected via 10'-0" flex hose.  My question is what size should the main run be? 6"? 5"?  Would it be okay to be 5" on the baffle outlet side and 6" on the inlet side?  My machine connections will be a short distance from the main duct, 2'-3', and 4".  The total duct run from the dc to last tool would be about 30'-0" with 1 turn.  The DC has a Wynn filter.  I would like to duct the dc to minimize moving the dc all over the garage and around all my machines.  Is this plan viable?  Is there a easy way to convert the impeller cover to 6"?  Are there after market covers available?  I that a good idea?   I'm such a noob! :-X 
Any advice would be greatly appreciated! :D

Well I finally finished my first Thien separator lid.  I am using a 31 gallon metal trash can and 4" hoses.  Prior today I have benn using the stock filter back on my Harbor Freight Dust Collector and the separator lid from Woodcraft with an Wynn filter waiting to install once the new baffle was complete.  Here are some pictures of the maiden run along with some modifications.  I had to add some weather stripping to the DC ring and Wynn filter.  I was getting some leakage.
I also added a stiffener to the DC ring which was getting bent from trying to originally seal the Wynn filter.  All in all I have to say everything is a radical improvement.
Even with the minor losses from the separator I still notice a net gain from the Wynn filter.  Thanks Phil! ;D

#1 - 2 piles of dust and chips from using the Woodcraft lid,  on the left from the can, on the right fines from the bag, almost equal in size
#2 - chips and dust in the can from using the Thien separator
#3 - fines in the DC bag, not even a 1/2 cup WOW :-*
#4 & 5 - my new separator
#6 - weather stripping on DC ring
#7 - weather stripping on Wynn filter
#8 - stiffener for DC ring

I am about to build my separator lid and I have a couple of questions about the connections between the inlet/outlet points and my flex hoses.
Am I missing something? The id of the flex hoses is 4" and the od of the fittings are 4.15" to 4.25".How are you making these connections.  After reading "here's the plans" several times and scouring the forum I have not seen anyone discussing this.  Please explain what all you have done to address this.
Thanks in advance.