AEA Anyone machine an AEA Zeus 72 cal. poppet valve?

Has anyone made a new poppet valve for the Zeus 72 cal and out of what material? Also... How big in diameter is the poppet valve and valve housing hole? Are these bigger valves are also breaking/failing like is reported on their smaller big bore brethren.
Delrin would be best. Also make sure you don't oil it when putting the stem on it will break after a couple of shots...