i believe that would work great as long as you are fairly consistent in the way you hang your tarp & hammock. and i think a lot of you are.
i tend to hang my tarp a lot higher than the hammock.
but, yeah, with a pocket that has something in it to add a little weight & keep it from blowing, that would certainly do the job.
it sounds like a good project for testing.
don`t leave the CREATOR out of the creation!