Im my opinion choose no rubber edge seal. The factory Road Glide seal fits like sh*t and looks kind of like a kit car after thought. It comes up short at the edges and does not fit evenly to the fairing. I chose to install a 1/4 inch foam seal behind the shield between the mounting screws. I purchased the stick on seal material from Wal-Mart. I think it has a much-much cleaner look and is sealed perfectly against wind and rain. The black out area at the bottom of the shield hides the seal perfectly. It has a superior seal over the factory rubber edge seal.
The only issue with not using a seal is that there is a large opening between the front and rear faring directly under the shield. This is over the radio and electronics. Dust, bugs, rain, etc. can easily work its way into the faring without some-sort of seal at the leading edge of the shield. You could use a weather seal purchased from home depo or Ace Hardware if you want to save the $19, but you should use something.
FWIW, clearview uses double shielding. Their leading edge strip is a million times better than the OEM, but they also put weather stripping on the shield that covers the inside of the faring gap as well. CV will sell thees seals even if you don't buy a shield from them. Just give them a call.