E85 fuel system setup

My Quickfuel 1900 bypass reg has the vacuum barb too, but the holley XPs do not have the vac port like other carbs.

I am trying to figure out why this setup is necessary. I have a diagram in which I can run his suggested setup and only need a couple more fittings, but wanted to see what others thought since quickfuel and aeromotive suggested this way that I have it. So it's not that big of a switch to do anyways, I just wanted to hear others opinions!



Here is my setup and the diagram mark suggests I should do