That compression fitting is definitely reducing your flow by a lot! What is your purpose for reducing it that much? You should probably leave it 1/2" for all of your fittings.
FEDERAL REGULATIONS
http://www.ecfr.gov/cgi-bin/retrieveECFR?gp=1&SID=b42343493f26258d1eb8b9c1e9bac637&ty=HTML&h=L&n=27y1.0.1.1.20&r=PART#27:1.0.1.1.20.1
STATE REGULATIONS
http://michigan.gov/documents/cis_lcc_brewdetail_57148_7.pdf
PROBREWER.COM
http://www.probrewer.com/resources/
The working part is brass "Place the brass nozzle with bead into the fluid container.". May want to de-lead it first. Don't know what the tubing is made of. May not be food-grade, may leach chemicals.
http://www.theelectricbrewery.com/ventilation
"Electric based brewery: Divide the element size (in watts) by 17.6 to obtain the required CFM (cubic feet per minute).
In our case we use a 5500W element in our boil kettle. 5500 / 17.6 = 312 CFM.
We therefore require a fan that can move a...
For just under $30 more you can buy your own 24" x 24" sheet of the stuff from McMaster-Carr 9358T58.
But then you'd have to cut it to 15" dia. yourself and use the scrap for something else.
If you found a use for all of the scrap, you'd save about $0.22/sq-in.
That's like saying if you only have a 100W lamp plugged in, you should only have something like a 1 amp breaker.
The breaker is sized for the wire it is protecting, not the appliance hooked up to it.