I'm currently trying to seal my shrink plastic keychain designs with Mod Podge but I can't stand how thick and gooey it is. I cannot get it to smooth out if I use it straight from the bottle. It's streaky and blobby. Before Mod Podge I was using nail polish which flowed very nicely and had very smooth coverage, but it's too expensive and I want to use something actually intended to be used as a sealant. I noticed Mod Podge is water based, so I was wondering if it would still dry and seal properly if I mixed it with water to make it run and lay smooth. Also, is Mod Podge waterproof after it dries? It's important to me that these are waterproof. Will mixing it with water change that?