...though Keltham may also, having said that much out loud, also carry out the strategy of starting from a random open-page flip like that, and reading forwards from there, or backwards, which means we need several pages forwards and backwards in each direction if we don't want to get caught like that immediately...
It's still better than losing immediately, if Keltham tries it.
Cheliax and its history, books about gods that will mention Asmodeus, books about afterlives that will mention Hell -
First priority, single two-page spreads of open books. Second priority, sections that go two pages back and ten pages forwards - the further forwards they can go, the sloppier they can be, because the faster Keltham will probably be reading. If they produce those by rewriting another book, then maybe, if Keltham is reading through all of the ten forwards pages, they can manage to rewrite more of that book, fast enough to keep up with him -
Korva Tallandria should be looped in on supervising this.