We have a 3008w 2013 windjammer, the big slide out for the sofa and dinette is rather large, it also has topper on it. When it rains it collects a lot of water. What do people do to prevent the water from pooling on it.
I'm not an expert on slide out toppers but I can tell you what a friend does to stop pooling and flapping. He uses an ordinary balloon or beachball. He blows it up and pushes it with a broom under the topper. It creates enough lift to let the water run off and helps stop it flapping when the wind gets up.
I'm sure that you will get some more sophisticated answers to the problem but his seems to work, at least for him.