WSM Disposable Water Pan Liner

I think it's a Great idea. Foil is not cheap either. At the price per I would use them. Hope they will come in 18.5 also.

Good idea, but I have no issues like you described. A piece of wide HDAF covers my 18.5" waterpan just fine. And if it does leak a little, it's only the water pan. Wipe it out with a paper towel and move on.