Curtis beat me to it. For a lower priced product you will want to get to 3-5% if possible.
Your back-end process sounds strong. Do you have a lot of JV support in place? Meaning, you will want to make it extremely simple for them. Ideally you can provide them with converting e-mails, and even custom landers if possible. Any type of *tested* promotional materials are great to have in place so it is as plug and play as possible for them.
You guys with more experience on this thread, for a product with a $19.99 price point that is converting so well on the back end, do you think it would be more enticing to offer a 100% on the front end to JV partners? This could make it more enticing and Shawn will still get the buyers list and back end. Feel free to rip that idea apart =D