question is, will it hold its seal with 4 gallons of water at 150F with 12 lbs of grain?
Your best bet is to use all 1/2" parts. The rubbermaids and igloos must have a tighter spigot hole.
Primary: English Mild
On tap: Pale Ale, Lancelot's Wheat, English Brown Ale, Steam Beer, HoovNuts IPA
Bottled: MOAM, Braggot, Raspberry Melomel, Merlot, Apfelwein, Pyment, Sweet mead, Cabernet
Gal in 2009: 27, Gal in 2010: 34, Gal in 2011: 13, Gal in 2012: 10