I am looking to replace a high voltage mosfet on a switch mode power supply but am unable to find an exact replacement (2yr lead time). I have been able to source simular mosfets but they differ in gate capacitance and drain-source on resistance. How can I modify the circuit to accomadate these changes. Can I simply change resistors to make the rc an resistance value match. Any advice would be apritiated as I'm still a novice in this area.