I don't know a whole lot about Masdies since I only have one (well, had until the box it was in disappeared on its way to an orchidsitter), but I think it's fine to mist the surface of the media. Rot is less of an issue with them. I would mist the sphag at the surface to keep it damp until the sphag in the core of the pot dried out a bit more.
__________________ Camille
Completely orchid obsessed and loving every minute of it....