In case you have not figured it out the Hennessy Hex is big enough that trying to replace the smaller stock tarp in an all in one setup is tough. It works a lot better on it's own suspension. Given that any comparable size tarp will do.
Thanks very much everybody. I cannot even tell you how helpful all of your suggestions were. I took a close look at all of the options you presented, and I think I'm going to go with the Warbonnet Mamajamba. Seems to be offer the best of all worlds with a nice, light weight at a great price (given that they're currently one sale).
"I never came upon any of my discoveries through the process of rational thinking." - Albert Einstein