HF top hat build

[tharris]

Hello everyone.  I've been doing a lot of reading here and have decided to build a top hat.  I have decided that I want to build it very similar to the one pictured. 
Question#1. I am a little concerned about the cone shaped portion inside the ring, whether it should be removed or not.

Question#2. Do I understand correctly that the outlet pipe should be elevated off the baffle a distance equal to .5 the diameter of the inlet?

Question#3.  I plan on incorporating vane style air straighteners inside the outlet pipe, but I can't seem to find any info as to roughly how long they should be.  Due to height restrictions I would like to mount the blower direct to the separator, so there may not be a tremendous amount of real estate in the outlet pipe.

Anyway yall,  I really appreciate any help.  I am not necessarily  intersted in building the most efficient separator possible.  But I am willing to but in a reasonable amount of effort for some reasonable results.  I just don't want to get too bogged down trying to build a finely tuned machine.  I certainly don't mean any disrespect to those that have or strive too!  Lord knows I wish I had the time to as well! 

Thanks!

TJ