hey guys i have a memphis shades batwing, i have their 6.5" flare shield, it works great for me, but going on a long ride coming up with the wife (to be)...hence need to please her, was thinking the 9" shield, might need more so she gets out of blast zone, any suggestions

 

I'm not sure what your height is, but to make sure the windshield fits you, you have to measure from a sitting/riding position- the tip of your nose should be level with the height of the windshield. If it's over, then you would end up looking through it, instead of over it. The taller ones will be better for 2up.
I too have the 6.5" flare and surprisingly works. I put a 9" shield on just to try and it's the perfect height for me(as measured above). But I'll be keeping my 6.5" flare and use the 9" in the fall or winter. I ride 2-up with my son and daughter and they have no complaints back there
Here's a few pics with the 9" shield for comparison:

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And the 6.5" flare one: