I ordered some clay from the Alec Tiranti website last week and got it yesterday, so I’ve just tried my hand at modelling with Chavant NSP (Non Sulfurated Plasteline). I’ve tried chavant NSP before, but not the Hard variant.
I can only say that I’m very pleased with it’s performance, it’s simply great to work with. It does require some heating before it becomes very moldable, but that’s not really a big workflow issue. I really like the firmness of this clay, when compared to something like Super Sculpey which has previously been my modelling clay of choice.