Hugel bed questions

So its now early July and I plan to have my hugelkultur beds built by the end of July perhaps early August. I live out side of Memphis, TN (Zone 7a) and I was wondering when I should plant and what I should plant. Since it will be August. Should I shoot for winter vegetables, what kind of cover crops, nitro fixers,etc. should I consider. I am aware that I will have to find what works best through observation, however, I was wanting maybe a few suggestions. Thanks.