I did this also to my HG 4 seaosn tarp for the door tie-ups. (To keep them rolled up when they are not needed, ie; most of the time)
It's quite neet and easy to do. Just means when they are tied up it's all quite taunt. I got better results from this method than tieing the doors from the same side together or diagonal doors off etc. I placed the tie-off so when the doors are rolled up there is like a small 2-3" cat cut to the edge. Like I said it's nice and taunt.
I have some pictures but they are on my thumb drive at work... no help there for the weekend.