Hey all. Thought I'd share this here. Since I found it likely be impossible to fit a full face helmet in Vespa's Primavera/Sprint topcase, I opted instead for the similarly sized Givi (b29n) case which could. I was bummed because I much preferred Vespa's perfectly seat matched backrest, compared to Givi's. Turns out Vespa's backrest fits just as perfectly on Givi's case. The case's rounded back was a dead match for the curve on Vespa's pad. All I needed was to measure out the distances for the screw holes. Maybe this is newbie stuff, but who know's, could benefit someone on the fence about cases/back rests.