Just thinking about your setup a little bit more and I was noticing that the hose barb looks like it might be plastic?? That being said, that is probably not a good idea to install it up against the grill, so I was thinking that maybe your local hardware store might have a metal threaded barb fitting that fits your hose, maybe a brass, or stainless piece would be optimal to prevent rust or corrosion. Just kinda wanted to throw another idea at ya:).
22 1/2 WSM
1971 22 1/2 Weber Bar b Que kettle
Weber genesis silver c (gasser)
Mini WSM (gold)