I have always thought that having the extra support from a ridgeline would keep the tarp holding up better over time. However, this past weekend I got a new (longer) chord and when I was on the trail I ended up scrapping the ridgeline idea, took my old (short) ridgeline, cut it in half, and used the two pieces on the ends of my tarp instead.
This was a quicker method to do what I had, but after I got to looking at the tarp it looks like its designed for this method anyway. There is a single loop along the ridgeline (top seam of the tarp) with a tie-in webbing angled in towards the center then the very ends of the tarp have a double ring set. I tied the ropes to the single ring, passed them around the trees, and ran them through the split rings with a half hitch to secure it.
Again, the no extra ridgeline method seems easy, and less material. Should I put the extra rope in there to span the distance regardless? Is there any other benefit to having a full rope ridgeline other than the extra strength?
On a side note, I've always hung my tarp with the seam facing down. I think that might be backwards, but not sure it matters.