HELP!! Cabover Seal For Sleeper??

I am looking at getting a Pete or Freightliner cabover, so I can put a large sleeper to make into a Class C RV. But I would like to know how to seal between the cab and the sleeper. Since the cab will tilt forward for maintenance, I need a weather seal that seals in bad weather. How have people done this in cabovers? What is the best way to seal it when it is sitting or better yet, driving the OPEN HIGHWAY??

Thanks