I would say that if the Givi isn't working for you then you most likely need to look at an adjustable bracket mounting system, but try removing your mirrors first as a quick test as it could be them.
I've got a hybrid screen which is made up from a Madstrad bracket, standard screen with the Givi adjustable top section mounted on it - works perfectly most of the time.



There is another bracket out there too, not just the Madstad but I can't remember the name.