I did a gap analysis on the objectives vs Scott and my OCA book and wrote a series of blog posts (including practice questions) on the few things our book didn't cover. It took me so long because working on our OCP book was a higher priority.
I do mention fairly on that I think people should take the real OCA and not the Junior OCA. (I'm not subtle.) But if someone wants to take the Junior exam anyway, our book + these blog posts can be used.
It's also interesting because it lets you see what my book writing style looks like before any editors get to touch it. Which means there's probably errors . And the style is different because I don't have an editor to make me consistent on things.