29 if you plan on doing skirmishes
You automatically hit everything three levels above you. Every player you encounter in a skirmish won't be a level 29. And, if by chance you do happen to encounter a level 29, the miss percentage is very low. And in the one in one hundred chance that you do miss, if you miss, your scaling can take up for that miss.pretty much this.
apparently skirms aren't scaling, you'll need 29 for the hit.