I am remiss in not thanking everyone for their thoughts. I am in the midst of installing a water maker before launch. When I said to the Admiral maybe we want just two burners, she scoffed and rolled her eyes. To her (and lucky me), all trips and vacations are partly evaluated on the quality of the meals. We have set the inverter up to run the InstaPot through the batteries.
My plan, after reading all the replies, is as follows.
1. Leave things as they are for now. Installing water maker, solar, and a few other things will keep me busy.
2. When in the Bahamas next winter, monitor (BUT WITHOUT HER KNOWING) how many times she uses one burner, two burners, or three burners at the same time. If I let her know I was monitoring, she would skew the usage.
3. Based on the results, perhaps we'll get a two burner with an extra single, portable burner in the background.
In the meantime, if you are in the Bahamas next winter and see Losada, come over for a meal. And bring something that requires an extra burner.....