Specifically, the MacCat mentioned by the OP will work just fine. I used a Warbonnet BMJ for awhile, which would be very similiar in design to the MacCat, and it worked Ok but didn't give me quite the coverage I wanted.
If you already own a MacCat, but want to pick up an extra tarp, including the Clark tarp in your purchase would get you a very good tarp for not much money. IMHO, the Clark Vertex tarp is one of the best designs available.
"...With saddle and pack, by paddle and track, let's go to the land of beyond."