I would like to understand if there is a specific rule or if it is left to the master to solve problems such as the damage of dragon claws and powerful fist.
how should you handle it if a sorcerer with dragon claws multiclass to monk and takes a powerful fist?
1. best value 1d6 + extra 1d6 bludgeoning or slashing doesn't matter
2. bludgeoning 1d6 + extra 1d6 or slashing 1d4 + extra 1d6
3. bludgeoning 1d6 or slashing 1d4 + extra 1d6