I can tell you the best way to learn about plumbing dry fertilizer systems....do out and buy a Deere 665 and blow fertilizer with it.  By the end of the year, you will have learned every trick in the book to try to keep fertilizer flowing. 

The Flexicoil, in comparison, is a very poor teacher....it actually has enough fan capacity to cover up some mistakes...not so with the old Deere's, if it's not all optimal, it's gonna be plugged!