A:
There are a lot of factors that can influence the correct rod weight for inshore salt water fishing. For instance, where will you be fishing, what will you be fishing for, how large or small are the flies you will be using, what are the weather variations in your area, and there are others.
The best thing to do is contact the closest fly shop in your area you plan to fish and ask them lots of questions. You will learn who the professional(s) is and who you can trust.
If you find that you have run into a dead end, I would suggest nothing less than a 7-weight for most inshore salt water fishing.