I hike in steep mountains a lot. so, I use 6' lines on one side of my tarp and 10' on the other. I then mark each end of the ridgeline (short/long) so that I know which side is which before I pull the tarp out of the stuff sack.
I set my tarp so that the long tie-outs are facing downhill. They need to be longer because I am "chasing" the slope downward as I set the stakes out from the tarp. The opposite is true on the uphill side.
That's a really good idea. I guess the long side could also be the " porch",if you are on flat land.