That's essentially what I'm after right there. Most of my driving is on the street and while I expect to have to empty it on regular basis there is a chance I may forget sometime. Are all these tanks open inside or is there any that have a down spout/tube attached to the fitting to direct the mist down?

Raff- this baffle your talking about...How big is it? are you talking a few inches overlapping the fitting or the length of the cover? the ends of the "u"'s- are they closed or open?