help with specs for CR shortboard

Help, I am building a shortboard for solid overhead surf, surfer heading to costa rica. The surfer is 128 pounds, 5’4" tall, and currently rides a 6’4" shortboard with fishtail that is 19 wide 2.25 thick. I am thinking of a 5’11" length 18.25 wide roundtail that is 2.25 thick. with the widepoint back about one inch. thanks for your help… Darren

For volume, that board would be vastly smaller than the board he’s been riding. That would require that he be a strong paddler in order to ride a significantly smaller board. Is he? And where in CR?

Yes, the surfer is an ironman athlete, crazy strong paddler. (I wish I could paddle like this guy)… He is going to the Tamarindo area, and stay mostly in the north. Looks like I will build two boards for him now. A new shortboard, and a gun shape around 66 to 70.