I'm about 5' 10" tall and have found that an 8" or 9" shield works best for me. It allows me to look over the shield and provides good wind protection.

 

LRS Stealth 9"

 

Clearview 8" recurve works for me on my SG. I'm 6'2". I have a 9.5" Clearview that I might use for long trips (I'm thinking of selling it for $60.00 I'll pay shipping). Both shields are dark smoke.
http://clearviewshields.com/shop/product.php?id=11

 

I'm 6'1 and I use a klockworks 8.5" dark smoke with the stock seat on my FLHTC. I get a little buffeting over around 80 or so(errrr I mean 55..lol) but even then it is not bad at all.

 

I'm 5'8"/5'9". The top of the 12" stock shield on my EG was right in my sight line so I went with the 10" Fast Aire recurve in light tint and love it.

 

LRS 8" recurve, light smoke, no wind on me but the wife gets a little, and i can see over the top.

 

7.5" recurve works great for me. I am 5' 10". Good luck.

 

Mine is a 10" dark

 

6.5" klocwerks on my danny gray solo seat, 15" HD with my Hammock seat. Both put my nose at the top of the shield. I'm 6 foot.

 

Made a big difference.