I also use some Zing-it instead of shock cord, with a mitten hook on one and and a loop on the other. I can then stake them out, or loop over the tie-down. Lots of combinations. I stake the sides down fairly close to the hammock if rain is possible. In the photo above, I would reverse the doors tieing them inside the tarp. That way if you leave them open and awake to rain moving in, you can stay under the tarp to deploy them. With them tied to the outside, that's fine but you are getting wet(er) to go out and untie them and stake them out. Usually in the dark.
My latest tarp is cuben and so I got the ties where they roll up just at the end. Best of both worlds, I can hopefully untie and open them while under the tarp, yet they are not hanging on the hammock side and possibly in the way.
I take some extra stakes for the doors also.