To be honest I've often thought of selling my tobinators as for quite a while I had left them off the bike as I couldn't get them set up correctly. An MRA Varioscreen was quite good but not quite there. After a pheasant / varioscreen interface (

) I'm back with the standard screen with tobinators fitted. It's not bad but there is still some annoying buffeting.
This current setup reduces the vacuum effect behind the screen and almost clears the top of my head. Something like the laminar lip, which claims to smooth out the turbulent air coming off the top of the screen and gives a little bit more height sounds like it could be the solution for me.
Fingers crossed