We've had different versions of the “sausage mold”. What I would like to try is again the mold where the sausage is one whole part made of Resin. Having the sausage made from several parts didn't really help the release and it created gaps and cracks that hurt the silicone. Resin seems less reactant to the silicone and I think that it can work. It's also possible to CNC the mold and use polyurethane. More on that here