And not only what you are machining - but the very detailed specifics of EACH machining operation: tool pressure, feed rate, work turning rate, diameter vs speed control, metal temperature, cooling and coolant chosen, tool setup and extension length, machine type ....
"What size hammer should I buy?" is an equivilent question: Without many more details, we cannot tell you. Your tool supplier cannot tell you. Stellite is chosen because it has a wear resistant surface = hard to machine.