I'm 6'1 145lbs 17 years old i currently ride a 5'9 lost v3 rocket. I'm an intermediate-advanced surfer
No offense but if you were intermediate/advanced you would probably already know what you need. Be honest. You'll get better answers.
Best advice I can give is go through a reputable shaper and tell him what you're currently riding in good surf and be honest with him about your height / weight / age / ability, as well as where you will be surfing this board majority of times and he will dial it in for you.
Thats a nuts height to weight ratio! Im 6'1" and 197. When i was at my best weight a few years ago at 185 people were saying i looked gaunt. 40 pounds less and I would be dead.
if im riding barrels i got a Merrick Flyer Custom as a primary (pop out but whatever it performs well and i got it cheap) 6ft thruster, and a similar model by some shaper in Hawaii I also got on the cheap. A good barrel board should perform well, and be expendable/cheap. Thats because a good barrel will shred your board eventually, and unless your a trustfunder your not made of $.