Nice work.
I think for a small piece like this but you need to make 12 as you said (or 11 more), perhaps you can make a 1 sided cast in silicone and make resin castings of them very rapidly. For the silicone, you can get fancy and buy the real hobby stuff or you can buy silicone caulking (for bathtubs/sinks) + bakingsoda/cornstarch to make it less sticky for only a few dollars. Once the silicone is cured (but flexible) you can easily cast with resin.
RE: Devil Gundam: Trimming Toe [Leg Modification - Part 100]