I know it's not a Windex brand, but I put a little cheap one from Pacific Nylon Plastics, (or something like that), up top. It was only about 15 bucks if I recall, and it actually works very well. If I bother to use it.
What works well for me is, is I took a couple of tell-tells, and attached one on each rear stay about eye level, and that way, my eyes are kind of "on the road". While this is not as "accurate" as a wind indicator, it's a nuisance to be sitting in the cockpit, staring straight up in the air, invariably right into the sun, like I'm looking for aliens or something. Now, while I'm utterly certain that they are upon us, seeking out lonely sailors to probe, this is of no consequence to me. I would rather be looking ahead, watching the sails, or the next drunken powerboater bearing down on me. I can dodge them; but the aliens are going to get ya if they want to, I'd rather it be a surprise..