I had a similar issue and its not fully resolved yet, but I am either going to customize the cab so the snorkel can breathe or just put something on the rail that will keep the vinyl off of the snorkels. ive been testing this with a cheap tusk rear vinyl window and dont see this being much of an issue.
We have done a lot of work in the dust in cab abatement issue with great success.
Now, the result of this great success is that all dirt and debris ends up behind the rear window in the cargo area, presumably right where you might have your snorkles, this will not work out well for you.
If you have a cab, you better have any snorkles higher than the cab, or your air box will be full of junk pronto.