I have a similar problem with perfectionism. If you're worried about messing up the books you might want to try photocopying individual pages and coloring those instead. That way you can just throw away the copy and start over if you feel you need to, and knowing you can do that might make the experience into something relaxing rather than stressful. I used to buy fancy journals for writing, but I was always afraid to mess them up, so I started buying shitty notebooks from the dollar store and that fixed the problem. Anyway, it's something to consider. You don't want those awesome pencils to go unused! :)