Close, but not quite the cigar, markjia...
No matter where on the platter you're seeking to or from, so long as it's the same distance for the head to travel, the seek time is the same. In other words, the head could travel inward from the edge or outward toward the edge, but if it travels the same distance, seek time is essentially the same.
On the other hand, and you got this perfectly correct, the outer edges have higher sustained transfer rates. For this reason, as you highlighted, we're putting the large files on the outside partition; because this is the primary partition and thus carries the boot image, it will be Drive C:. Now, as we all know, our storage volume always needs to be larger.
Next point I have, which was also made earlier, and that Straker pointed to, is that whenever you install an OS or app to a particular partition, its files will only go to that partition (duh). Now, let's say that the installer of the OS or application sort of throws files all over that partition. If that partition itself is only a very small portion of the drive, then it only covers a very small portion of the platter. In other words, for OS or apps, which require short access times to perform quickly, and not much on transfer rate, installing them to a much smaller partition will yield the best performance improvement.
Now, in order to keep yourself organized and not go bonkers dealing with a zillion partitions, one would likely set up two and two only; one for storage and one for OS/apps. If the one for large file storage is taking up the outer tracks, then the one for OS/Apps will take up the inner tracks, especially since sustained transfer rate is less important. Moreover, the storage volume will definitely be larger, since, as I said, OS & apps typically don't occupy nearly as much space, which is why I quoted 2-12GB (although with the size of modern games, maybe even 20GB isn't enough!
). So long as the inner-platter partition is nice and small, it will keep seeks across it to minimum times.
Crystal clear yet?
PS There's one caveat and that is that because of the shorter circumference of inner tracks, a partition of a certain size would occupy a wider diameter spread than the same size partition at the outer edge; oh, I better stop now before all confusion breaks loose, if it hasn't already...