Hello, Wiahmation. I'm terribly sorry to be so late in my reply (again), I've been on vacation and away from my computer. So, if it's not too late...
I haven't used Ben Nye latex, but from what I've read online it's pretty good stuff. I can recommend balloon rubber latex from motionpicturefx.com, which is thin, so it needs several coats, but it's also very flexible and durable. Great for "skinning" a puppet. Hope you can use this info, and again, sorry for taking so long!
Hey, dude! Sorry I'm so late in my reply! ... I buy polyurethane or furniture foam at Joann's Fabrics. It comes in rolls or sheets of varying thickness!
Hey! Thanks, dude!