I am going to be taking pictures of regular books and not any special ones.How fast are you going to turn the pages? And are you going to use the flash at full power with your 1D X and EF-S 55-250 with your petal hood? I'm guessing overheating won't be an issue for any of the Canon flashes with that usage, but a spare set of duracells might come in handy.
Failing that, why not just buy these 'regular books' as e-books?
I do not want to pay for any books if I get can them for free.