2-Up Helmet Buffeting Issue with Shad SH39 Top Box - Givi D2122S and California Scientific Tinted Shorty

[Magnum099]

I know that issues with the FJ-09 Windscreen have been discussed endlessly on this forum, but I haven't seen much information about a particular issue I am having with my bike regarding a couple of specific windscreens. I thought it might be good information for anyone considering either of these. 

My bike is typically set up using the GIVI D2122S screen with a SHAD SH39 Top Box for commuting/daily riding/etc. I leave it in this configuration at least 80% of the time. It works well with just me on it riding alone, and I don't notice any annoying amount of buffeting or anything like that. It can easily run 80mph+ if desired without issues.

However, I ride 2-up with my wife sometimes, and I like to use the top case for short rides, or I will combine it with my Yamaha Side Cases for longer rides. Unfortunately, when I ride 2-up with her going ~60mph or greater in either of these configurations, I often get helmet buffeting using either of these windscreens. This is especially noticeable on the interstate. The wind will grab my helmet and jerk it left or right, often going back and forth. I am 6'3" and use a Shoei RF-1400 helmet. 

This also happens using the CalSci Tinted Shorty when riding 2-up. I rarely use this windscreen anymore though, I personally think the bike looks kind of goofy using this windscreen with a top box or side cases installed.

A couple of interesting notes:

1) This issue does not happen using the Yamaha factory windscreen. I may have found the only good use for the factory screen. 😀

2) This issue doesn't seem to happen with only the Yamaha Side Cases riding 2-up. 

3) This issue happens both with and without the factory hand guards installed.

4) This happens with the screen in the lowest or highest position, although it seems ever so slightly better in the high position.

5) My wife said her helmet doesn't buffet around like mine does, but she can see my helmet jerking around. I have a feeling this is caused by the location the wind is directed on the bike due to the windscreen design. 

Questions (some of which I will try to answer with further experimentation):

1) Would a Puig Clip-On Wind Deflector or something similar fix this issue? I haven't purchased one of these yet, but I am considering it. 

2) Is my helmet the issue? I have a Bell Qualifier Helmet I will try also. I am curious if a different style/shape helmet (such as a dual sport) might resolve this. 

3) Would a different top box fix this issue? Perhaps the aerodynamics of the SH39 are not ideal for 2-up. 

It is annoying to the point that I will not go on rides over ~30minutes in this configuration 2-up, instead I will go with only the side cases or change back to the Yamaha factory windscreen. 

Just curious if anyone else has experienced this or something similar?