2+1 Fin Setup

Hi All! I am new to the forum. Been surfing for a few years, but just starting longboarding. I recently picked up a 9' Pearson Arrow with a 2+1 fin configuration. The board is mint, but the fins are shot. Would like to keep the tri-fin set-up, but looking for input on what sizes and types of fins others recommend. Most of my surfing is done here on the east coast of florida...2'-3' if i'm lucky, but at least the water is warm...