I recommend Treasure Coast Air. I've only been there once, but the manager (I think Michael?) was very welcoming and the FBO had a nice relaxed beachy vibe. It was nice hanging out on the back deck sofa for a bit and talking to him about his sea plane operation. It's also in sort of a nice sleepy area of the airport so you can take your time without being too noisy or under any sort of pressure to move. IIRC their self serve pump was also right next to the FBO so you don't have to go way out of the way to use it if needed. Have fun.