This is just plain stupidity. Why do you think they put a zener diode to detect axu winding over voltage? When you hack Z1, you are defeating its coil OVP feature, and literally the primary side MOSFET can blow up, and secondary rectifier diodes can blow up.
I don't mind modding voltage to, say, +-10% or even +-20%, but +100% is just insane. You'd have better luck replacing the xfmr with a proper one, or use a voltage doubler rectifier on secondary side.