No reason why 2lb foam wouldn't work, but they don't say if it's a flexible foam or a rigid one. Most of the 2lb foams I've found have been rigid ones, and you need flexible for dreds. Smooth-on sells a 3lb foam, as does kryolan, as do a few other places. Some of them are self skinning, some aren't. There are ways of getting around the problem if they're not self skinning, but it takes time, experimentation and sadly, money.