Many thanks LCUF for the links. And AlwaysAisle, that was the definitive info that I was looking for, much appreciated. Nothing else on the 'net (in English at least) that details what you had said, even after searching for an hour. Lots of info with regard to the racks on the Mu-Sky, but hardly anything on the 'regular' Limited Express.

Will pay the ¥360 surcharge for the reserved seat as recommended for one of the two types of limited express trains and will keep my fingers crossed that I can secure space for my bags. If the racks are roughly the same size as those on the N'EX and Haruka I think I should be ok...