Depends. If you're only using him in the rancor raid, and you don't have either dengar or TFP, you should get him up to 80%+ potency for it to be effective. If you have TFP or dengar, you don't need potency mods, so just get him as fast as you can so he reduces TM as often as possible. Same goes if you were to use him in arena, you want him as fast as possible.
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