Greetings,
Mr. A. EXCELLENT question. I'm experiencing the same things but rather than slopping on the windows, my handrails are taking a beating/wetting.
From what I've seen on boats that are the same model as ours, originally there was a teak trim piece along the outside of the side deck overhang. Ours is absent.
What I have been looking for and I don't know if it would be applicable in your specific situation is a large "J" track to fit on the outside of the overhang and channel the water, either to the stern or to a central spout of some sort that would direct run off outboard of the railings enough to minimize soaking the railings. Something like this but in a white or complimentary colored plastic. I can find small profile tracks (1/2" to 3/4") but I would much prefer something at least 2X as large.
Just found these RV things...
http://www.ebay.com/bhp/rv-gutter