I don't want to throw cold water on your project, but there is no way in the world you are going to be able to test this out for EPUB in seven days. If you're not willing to spend some money to subscribe, at the very least on a month-to-month basis, you might just as well throw in the towel now.
That out of the way, if you're going to continue with this, you should be aware that EPUB is very dependent on the reader application and the choices the user makes. If you're thinking fixed layout, I would have to advise you that you are likely to be in for a world of pain because there's very little support for it.
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