Magic,

I used to throw a closed cell foam into my Clark's Jungle Hammock.  I actually did it to achieve the degree of the flatness you get with your Hennessey Hammock.  I don't see why you couldn't do something similar with your Hennessey.

Of course, if there was a fire overnight, you could have all-hell-to-pay in trying to get out of your contraption in a timely fashion since you access/egress from the bottom (versus from the top, as in a more civilized/functional style of hammock such as what I use).

The Clark may be more expensive than the Hennessey but - other than the flat sleeping - I'll take the Clark any day!  Frankly, the pea pod concept suits me better, anyway.  

Later,

Jimbo   8-)