Maybe I am not understanding your post accurately - is the issue that you basically don't have a stud that lines up with where you want to start/stop your rack? I have the Hyloft racks which I imagine are the same as all the others, but they are only bolted in on each end.
You can see here - I used plywood on the top one as I needed the end to be attached where there was no stud, the bottom straight through drywall onto studs at both ends.
The plywood is 1/2" I had lying around and practically speaking I can find no difference in strength in either.
-Mark