We just let it puddle, eventually it dries or the wind comes along and moves the awnings around and out comes the water. Have not noticed a problem with mold or anything like that. That said, we have never stayed in a rain forest for months on end.
Thank goodness for that! HA HA As the water dries, the spring tension in the slide toppers kicks in and tightens up the awning. So, we handle by not handling.