I have a 30Gal blichman boil kettle and I need pretty much 10Gal to cover the element, but wouldn't use less than 12Gal.
I'll be honest about my experience with cam locks...a long time ago I stopped hooking\unhooking the locks...I've been pulling the hose right off the hose barb of the cam locks if I need to disconnect a hose...I'd be content with noting but hose barbs on all my kettle and pump fittings...as long as the hose barks are slightly bigger than the hose ID. All my hoses fit snug and I have no pressure in any of my lines....thats my experience anyway.
Beautiful controller!