I am having some difficulty following your description. Your use of the term summerbeam might be incorrect. Can I suggest that you consult the timber framing glossary.
Your mention of passing braces has caught my attention and I would appreciate if you could photograph this feature upon your return to the barn. A passing brace rises from the lower section of a main post, passing over the mid rail where it is lapped eventually being morticed into the underside of the wall plate or in this case a connecting girt. As discussed previously connecting girt barns with common rafters do not really go together unless the barn is also equipped with another "flying" plate outside of the plane of the long wall and in the plane of the roof so it would be important to get photo shots of this design aspect as well please.
