Just so you know, waterproof is nice but not absolutely 100% necessary except in the case of a rock solid gully washer as we call them here in Texas. I've run open pods in so much rain I can't say and only one time did it ever rain enough to affect them and that one was raining so hard I could not literally see at all to be moving while driving anyway. All the rest I had to have the bike running as I had no car for many years, bike only, so I drove in the rain and countless times. The Kawasakis I rode in downpours and no effect on the open paper element. And at a facing up at 45 degree angle. On pods, the foam ones if not dry of oil will repel water far better than K&N type gauze, the cel openings on the gauze are too big (run one to draw the oil down and hold it up to the sunlight to see all the open pores in it). The K&N are also relatively thin too and why you see those holes, foam (UNI type) is more convoluted and much thicker and why they do better in rain. They also trap dirt much better than K&N do. If oiled correctly the foam simply shunts the water to the bottom of filter by gravity and the water then drips off the bottom. I never ever ran into water ingress issues except for that one time and that I note was K&N type filter. By far a worse problem on the DOHC was water during hard rain running down the inside of the front fuel tank notch at frame to then stack up enough to wet the coils out to try to drop spark. By experimenting I found that if you dropped speed to 50 mph the water stackup rate would slow down to not do it, any time I sped up the coils would then short until I slowed back down. Weird, huh? The Kaws did the exact same thing to shock you through the clutch cable lever as the engines were newly designed with rubber mounting, but on them I found that if you ran a dedicated ground wire from engine to frame the issue stopped 100%. Kawasaki found it too, the next years had the harness modded to do the exact same thing. The UNI podded CB550F I have has had no water issues at all but I don't drive in rain like I used to either. I blocked off the rear filter case (two big pieces, front and rear, on a 550) on that one to make a waterproof glove box of sorts to hold things. The DOHC with open lower OEM filter showed no water issues at all due to the modded filter. The filter just gets dirtier faster.
90% of my bike riding time the bike was stored outside in all rain, so there's that. They had to start and run correctly right then or problems. For some reason I never end up where there is garage space for a bike. Even now the 550 is out in the open.
A couple points. On a UNI foam filtered bike with pods you can shove them forward to squeeze out excess water before cranking bike up. I used to practice that if coming out from work to an all day rain soaked bike. Try that on K&Ns. And one thing you must have running them or any other modded open air cleaner element. There must be a full length rear fender front section to keep throwoff water from tire from literally flooding the air cleaner area, that disappears on lots of custom bikes and you will flood engine out with water not having it in place as a deflector.
Food for thought, yours and do as you will...........