Tophat inlet/outlet size and position

[kmerkle]

I am in the process of building a tophat separator that will sit on top of a 55 gal drum upstram from a HF 2hp dust collector.

I have installed a 4" S&D outlet, with the tube bottom 4" above the baffle.  I've built an inlet box 6" square, which will house another 4" S&D tube. 
I plan to connect the inlet to a 6" header with 4" drops to various machines.

My questions
1. Should I increase the outlet tube to 6" or will 4" flow well enough. 
2. Should I make the inlet box the full height (12") of the tophat, or is it just as good to keep it square -as shown in the pic.
3. If I keep the inlet box it as is, is it better to attach it to the top of the tophat?
4. If it is better at the top, is the position of the inlet on the circumference, with respect to the solid 120 deg. part of the baffle still important?

Thanks,

Kurt

[retired2]

Q1). 6" has less line loss, so it would be better.  However, if you are attaching a bellmouth, it might be too large since your inlet is 6" wide.  The combination could result in waste stream bypass.

Q2). Don't make the inlet box full height, it defeats the purpose of a 2X separator.

Q3). Definately attach it to the top, for the same reason as Q2 response.

Q4). The most likely answer is yes, but I'm not so sure, and I have not seen any guidance from those who have built 2X separators.  In fact, any feedback from 2X builds has been scarce.