I tour with a tarp/bivy setup and am quite happy with it. I've been in rain, high winds, freezing temps, etc (not in the same night though!) without serious problems. Mine's homemade out of Tyvek for $10 but I'm sure your legit version will work even better. I remove my front wheel and use that to hold up one end and use my bike for the other.

Here's a picture of a sloppy pitch in the Guadalupe Mountains in Texas from last week: