I've got about 2500 miles on my 9" KW Sport Flare. I had the opportunity to test a 14" for about 100 miles, and it was the $h!t. Put me in a nice bubble for wind protection and the stereo was worlds away better. But I just couldn't get over how tall it *looks*. The 9" is sexy as hell. And definitely better than stock, as far as reducing turbulence around the face and forehead. But still pretty breezy. Both the 9" and 14" were hard to look thru. LOTS of distortion in the "wave" between the sides and middle. If you don't look THRU the screen, it's a non-issue. I did compare both shields back-to-back, and chose the 9" purely on aesthetics. The 14" wasn't too high to look over. If I had to do it again, I'd probably opt for the 14".
I'm 5'-10", with long arms/torso, and short legs (32" inseam). Keep in mind, that this is my first touring bike. The only windshield I've had was on my '08 Softail Deluxe. So- no fairing to help with wind reduction. And I've got sensitive eyes (too many years welding, and regularly abusing my vision). Dust, chill, and wind always get the waterworks flowing. All other bikes I've owned have been knees-in-the-breeze, and bugs-in-the-teeth. And I'm kind of partial to old habits.
To put it in perspective.... With the stock shield on my RGS, I had to wear gasketed glasses. Even with the stock shield, I was having issues with the watery eyes. The KW 9" cured that. So, I can wear regular sunglasses or non-gasketed riding glasses without issue.
If you've got a KW dealer nearby, they might loan you either or both for a day. I got my loaners from J&P Cycle in Sturgis. It had the word "DEMO" screenprinted across the front, and they kept my stock shield as collateral.
Good luck on your quest.