I did mine in a lot simpler fashion...
I figured that I would never see water above the windows, so I used a top of the hood scoop that is ducted to the air box. Works PERFECT.
I also gained a little bit of oomph on the freeway from the ram air effect.
Some details:
Scoop -- eBay item, commonly sold under a bunch of brands - $10.
Ducting hose: Common RV flexible poop-pipe with fittings - 1 - 90* (air box)and 1 - 45* (hood) - $15. The hose is holding up VERY well, and you get 10' in the box, so it is good for 3 applications if it tears.
How to install:
I pulled the battery and air box, then removed the factory inlet tube completely (so long water vacuum!)
Where the factory inlet hooked into the air box (a rectangular-shaped hole) I used a hole saw and cut it to fit the 3" duct fitting (90*). I used silicone to hold the fitting in place. I also used a file and a grinder to trim the edges of the fitting flat on the bottom (will become evident when you look at it) and the hole in the box. You could also glue it in place, but the silicone seems to work well.
I also drilled a few drain holes in the bottom of the air box to deal with any rain or other water that might get into the box. Rain while moving is no big deal, but puddled water in the box is a problem. I used a 1/4" drill for this purpose and drilled around 6 holes in strategically placed spots for best drainage. No worries about contamination, as this is below the filter. Also, the holes are not large enough to let in a lot of hot air versus the free-flowing source coming from the ducting to the hood.
Attach the hose to the fittings (press fit - no clamps needed).
Hole saw a place in the hood (right next to the AC ducting, to the rear of the hood) to fit the duct fitting (45*). Insert the fitting into the hood from the top down. Use silicone to seal it to the hood, and also two sheetmetal screws with fender washers to apply a clamping action to hold the fitting in place. Attach the other side of the duct hose.
Clean the hood well, then stick the hood scoop over the hood using the double-sided tape already applied to the scoop. Make sure you align it well - you get one shot!
Job finished. Total time for this mod -- < 1 hour start to finish.
You can just see the scoop peeking over the top of the left side of the hood in this shot... It SAVED my engine in this hole, which was up to the pin stripe on the side of the body.
A better view of the placement on the hood.
An "inside the truck" view.