It's really interesting to read what all you inventors are thinking about doing to rid the water from the toppers on the slides. I'm not bothered with any toppers, heck, I don't even have a slide, but still interesting. On my older A & E awning the company place three or four brass grommets about 4 inches from the outside roller so in case water was pooling on the awning the water was released from the awning and not stretching the fabric. Putting some relief holes sounded like a good idea. Someday I'll have take a look at someone's problem to see what you all are talking about. Have fun experimenting with the fabric and if anyone wants me to hold the water hose while testing your personal invention I'd gladly help with it.
Mandy