what you can do is just push the 2 EZ-Ups together.
Get some clamps.
Start in the center where the ez ups meet, and pull both pieces of fabric together, fold up and clamp as high up as possible, then going out from the center place the clamps a little lower and lower.
Kind of hard to explain but what your doing is basiscally making a rain gutter and all the water will flow off the sides and not into the EZ Up.
It's rained at every competition we've been at this year and this always works perfect.