There it is, all glued-up & finished. Overall I'm pretty pleased...definitely hit a few snags. But I know how to make a better cover next time.
all paper edges were coated in multiple layers of white glue, both interior and exterior. Makes for a surprisingly solid structure, which was great considering how much material I was removing from the text block. I used the original foam insert from the packaging to lock the tablet in place, but that meant the remaining page borders were between 3/8ths and 1/4 of an inch. So it certainly needed a lot of strengthening.
All that remains is to air it out to remove the smell of E-6000 (really good industrial glue)...