I've been testing a pole mod on a Hennessy stock asym tarp. Works pretty well. The guyout lines are attached to the support pole of my stand in the picture but it would also work in the field to attach to a center stake. Simply pull on the line sliders to pull the tarp down to whatever arch angle you desire. So far this has worked well in the backyard.
The pole mod removes the tarp ridge slop and tensons the whole tarp quite well.