That's going to be one expensive die! I think its M24x1.5
If you can wind it on almost all the way with your hand, you should be OK to just leave it. You could oil the threads if you wanted. I can't think of ever being able to wind the nut on with my bare hand, they always took some wrench work to get them to the drum. How much torque do you think it takes to turn it before it seats?