Also, you can do a "hot coat" to extend your re-coat time: just brush on a thin coat of raw epoxy wherever the cloth will go to keep the surface "alive" for another cycle. Far, far, far better than waiting for cure and sanding!
Edit: and if you do end up needing to wait and sand, let it cure hard and use a good mask when you sand to avoid epoxy sensitivity, something you may want to read up on if you're not familiar.