side note: water into the engine is not so bad. Mechanics, and myself, used to clean the cylinders and valves by spraying water into th eintake to give the insides a steam bath. There are engine systems out there that use a fine mist of water sprayed into the intake to help with economy. The water turns to steam, expands and helps spread the fuel particles out over the piston head to give a more powerful burn. These systems are expensive so not widely used.
The downside is water getting past the piston rings and into the crank case oil. I used to spray clean mine right before an oil change just in case.
Wet paper filters is a big issue, but it sounds like you have the right idea to jerry rig something to keep the water away.
