Surfing Waves

Hey guys in about 2 weeks im going to Puerto Rico for a surf trip i have given up on the idea of bringing my own al merrick board on the plane so i will be renting a board in Puerto Rico. The guy who owns the surf shop wants me to give him the demensions of the board i want by tomorrow so that he can get the closest dimension he has to it. What do you think i should rent out. I'm gonna be surfing around San Juan so i cant imagine it getting too large. I'm a beginner (1 Summer of sruggling on a shortboard) I'm 5'8" and 120 Lbs. I want to be able to catch the waves but still be menueverable to take control of the better surfing conditions there. Should i go Fish? What do you think i should get?i wont be needing anything over 6'10" (i can catch waves with boards that are 6 ft)

that probably depends on how your almerrick feels and its length.
If surfing is feeling hard, sketch on the al merrick i would reccommend getting something wider/longer.
If you mastered the al merrick you might wanna try something shorter! (depends on size of al merrick)

I called the surf shop dude today and he's holding a poly 6'7" x 2 1/4 think it'll work?