3. Toughness
6. Bonus Ranged Damage
9. Bonus Ranged Damage
12. Lifegiver
15. Lifegiver
18. Bonus Ranged Damage if you take 2 nuka colas, then you will be able to do 2 bursts in a turn. Otherwise, i'd say better criticals.
21. Toughness.
And Trait: Bruiser is a big no-no, you'll get -2 AP when you take it, so it is NOT recommended.