PLA alternative

I am venturing into metal casting and the person in charge of the casting process has only used PLA resin in the past. She is very comfortable with it since it evacuates the mold completely leaving a clean mold. All of her clients use FDM printers to create their objects. This requires excessive polishing in the post production process.

My question is what resin would be the best substitute for PLA in making casting molds fro metals.?