Skis for My Little Brother

I've been helping my little bro pick out his first set of twin tips for this season. He is a great out of the park skier having raced in the past, and a beginner in the park. He is too big for a kids ski but small on the adult twin tip side. We have it narrowed down to Line Masterminds because they will be soft for him and light since they're cap construction. I'm not sure how long to get for him though. He is 4'10 and weighs maybe 85 to 95 pounds. Should we get him the 147s or bump up to a 157? I'm thinking go with the 157 but wanted to see what you guys think.