I was messing around a couple of weeks ago and set up my new RR and a Wilderness Logics Big Daddy Tarp. My BD has a 144" ridgeline, so I wanted to see how it would work with the spreader bars of the RR. In short, it worked just fine and I didn't really even mess with the hang at all.
I had it pitched pretty low, so here is a side view showing the coverage:
It is touching the sides a bit, but once I got in the hammock it slipped below the sides with a little room to spare.
Here is a shot from the other side, same basic conditions apply.
In this side view you can see that the head end spreader bars push out just a little; I think that a side pull out would take care of that.
I haven't done an overnight using this particular rig, but I think I will do so without any fear of damaging the tarp with the spreader bars.