Think of it this way, can you deform the bullet by applying a crimp? If so don't do it.
do you need to crimp the bullet at all? only if you need to build enough pressure to burn the powder you have chosen.
In most cases crimping a cast bullet is wasted effort. Neck tension is a greater control variable. use of an M die is the best plan, custom modification to get the correct tension is where art meets practicality and results. JB