Where do you expect to instruct? You might want to take a course at a shop that will take you on as an instructor. But if the local shop doesn’t mind, I would go for warm water. When the water is in the low 40’s you will get cold no matter how thick your wetsuit. Are you impressed by the people who will be your instructors? That’s important as you will be a student to their mentor. I dive in the Caribbean a lot, warm water is recommended. But I took my DM and Instructor courses locally in Philadelphia suburbs, because the Course instructors impressed me and I now do teach courses with them. Caribbean GoPro courses are great, if you have the luxury of time for the course, some internship, and some fun diving. If you want to stay where you are, then a local course working into your schedule and instructing courses locally within your schedule may work better for you.