I actually talked with a factory rep at KW and he told me that the shields for the GL1800 won't work on the F6B. I'm not sure if it's because of the adjustability on the GW's or if the holes are different. I thought the same thing but apparently its a no go on the full size shields on the 6 - which is the reason I went with the 16" - not too mention if I need more coverage I have the OEM tall w/vent.
IMO if you want the vent option Clearview's Shields are probably the way to go. Forum members seem to really enjoy that product and judging by the picture you used for me to reference (taken from their site) you've looked at them as well