I will, but before I do. . .are you really wanting to go down this road?
it will open avenues in casting that are much wider.
but then again, if you master it, so much the better, then I never have to learn to cast,
hydrospan is a different type of mold making compound
depend on what you want you shrink or enlarge the target cat by, I've hear 100%
Its most often used, in my limited experience, in making 6 inch figure stuff shrink down to 4 inch scale.
I'll try to find a tutorial,
http://sculpt.com/catalog_98/CastingMaterials/HydroSpan.htmhere is the product... I'm not sure which kind you use to get it exactly right, but JFAK(if you see him around) actually had an online store where he sold nothing but diminished parts.