If you're 150l freestyling, then it's more longboard-type freestyle than modern freestyle, that type of sailing doesn't make you proficient yet for waves freestyle.
Still, don't go too far above 100l, freestyle-wave type board. Freestyle and speed almost contradict one another gear-wise: freestyle smaller sail for better control, speed = bigger rig. You may have to make a choice.
Try it at your usual spot first, on the strongest wind you can go out in. After getting used to the new gear and waterstarts, then go ocean-side and start on a low-swell day, perhaps NE at first rather than southerly for easier winds in waves.
Agreed with the guy who said to hold on to old one if you can.
BTW, we're all beginners, hopefully humble too

PS: Balmoral, haven't sailed there in yonks... how many boards out there on a good NE weekend day ?