Rather than sew on webbing (I am thread injector challenged), I use a continuous ridgeline, and adjust the tension on the tarp with a prusik at either end of the tarp. You don't have to pull the tarp tight at all, if the ridgeline is tight. There is very little tension on the grommet doing it this way. An added bonus of this method is that it's very easy to adjust the position of the tarp along the ridgeline. The Chinook is a great tarp for the money.
" I have not yet begun to procrastinate!"