Hi, why would you want the plate vertical? cant see any prob with how it is.
It should be fine slotting up to the holes (like a keyhole) the plate is definately stronger than the originals although your going to have to shorten the outers and the inner so why not just thread it all through before remaking the end up as in the book?
I havent done mine yet so its all theory at the mo but surely its not all that difficult.
Ray