I used to have a 2007 Breva 750cc and when I purchased the bike, it had a MG touring windshield already installed. That shield produced an enormous amount of buffeting so I removed it. I replaced it with a small Givi cafe fairing (no longer available) and it did a great job of keeping the wind pressure off of my chest and produced a clean air stream around my body & helmet with zero buffeting.
I sold the Breva due to having to stop riding for over two years due to health problems but my overall health did a 180 degree turn and I was able to safely ride again. I liked the Breva very much but couldn't find one that was anywhere near as clean as the one that I had sold. Fortunately, I found a very clean, well sorted V7 Classic that was nearby and bought it. It also had the MG touring shield mounted and again, I couldn't stand to ride behind it due to the excessive buffeting. I attempted to find the model of Givi that I had on the Breva but it and all the other similar Givi models were out of production so I found a cheap EMGO fairing on Ebay for around $60 and modified the not-so-good mounting hardware that came with it and it works as well as the Givi that I had on the Breva.
If your primary purpose for adding a shield is to stop/reduce the wind pressure on your chest, you may want to consider adding a small cafe fairing. This solution has worked well for me with both of the V7's that I've owned.
If you don't want to go the cafe fairing route, Dart makes a couple of small screens that will reduce that wind pressure (but they won't divert as much wind as a cafe fairing).