When developing film, if I can recall back to my high school photography classes, we hung our photo paper with clothespins from a line.. I wouldn't think that to be the best way to dry out a blotter due to gravity and what not. Personally, while I've never done it, I would lay the sheet flat on some sort of mesh like a cookie rack.
I don't see what the point of using a ziplock and sealing out all the air is. Just get a dish that's nearly the same size, or make one if you have the means. Either way, preparation is the name of the game. Make sure everything is in order before you start anything.