Great work, @Oxymandias! I can sense a future professional level sculptor here. I really like the details and the layering of surfaces going on. Great sense of depth with the coiled hair and beard as well.
I have never dabbled in casting models or parts myself with blue stuff, greenstuff or milliput, so I wish you the best of luck there. I’ve heard that blue stuff is the best way to go with moulds. I hope you get help and find a working way. Forgemaster @Nicodemus, what say you?
But I have some thoughts which, if not relevant for this sculpt, could perhaps be relevant for upcoming sculpts of yours.
Casters as an Option
Since the sculpt seem to be based upon parts of an existing miniature (2nd edition 40k Ork? correct me if I’m wrong) I’d be amiss to advise you to speak with a caster as an expensive but reliable option, unless you completely covered the shoulder plate and feet with putty and sculpting of your own.
If money isn’t an issue, than having a casting company make moulds and cast copies for you is a smooth way to go. It does mean waiting time, but saves you the hassle of dabbling with moulds and resins and whatnot in trying to multiply your sculpts. Of course, castings of a fully self-sculpted miniature can also be sold on the side via Ebay, or smoother yet, Etsy, for other collectors to purchase. Wink wink .
(I believe @tjub may experience a sense of deja vú here. CDO converters tend to be on a slippery slope toward casting minis.)
I know a few casting companies if ever you’d be curious.
Good luck, whatever you do!