Sy22 lead casting

If you have casted your own lead weight for the sy22 did you use the printed casting box printed in pla? Also did you use plaster of paris? Trying to get some info before a mold blows up in my face. This will be my first time casting. So I have my mold mixed 50/50 with sand. I figured I'd dry it until my next birthday 😂 in my filament dryer 😁