Just for the record (not that it matters), I run my stacks with mesh screens and these great little "gore-tex"-like boots called Outerwears on them. The outerwears keep dirt/debris and even water out of the engine whilst minimally impeding the air flow. I have done tests and verified this qualitatively by running covered and uncovered and connecing the bike to my 160lbs butt dyno. They have little to no affect relative to the screen mesh.
I used to run uni pods with outerwears on them, but due to their position it was very hard to filter out the rain. That led me to run stacks.
Looking back, I kinda wish I had stuck with the stock air box setup, as I would have no problems with rain at all, but at least now it looks cool!!
No..seriously though, now it performs better, and gets waay worse fuel economy, so I am happy.
If I ever get another bike, it is staying completely stock perofrmance wise. If I ever modify another bike, it is staying completely race-only and not my daily driver again! You can't expect a hotrod to run great in all conditions!
Anyways, I hope you run your engine with whatever the heck you want, but just do something! Don't sit around thinking about doing things...! Go out and ride that sweet hog!!
P.s. I'd do non-stack again! ;-)