It works for horizontal enter as well.. the only key that is missing from a horizontal-enter keyboard is the one between left shift and z, which is just backspace, so you can disregard it. It's just that with a horizontal enter key, the ; key is above the enter. With a boot-shaped enter key the ; is next to l, which makes it easier for me to hit it. I use the command line a lot.
If you're looking for a good place that does boot shaped enter keyboards then you can use Unicomp's Model M. You can rearrange the keys as you wish and they'll even print key caps with anything you want on them with the home row indicator tab, so you can put one on the h key.
The right shift key is covered only by the pinky finger of your right hand. The ring finger has the forward slash. If you give it a try make sure to send your comments over via bitbucket or something :)