Get a 10wt and be done with the decision making process. The vast majority of our SW fish are neither leader or line shy. A 10 will throw a much larger variety of flies in all but the very worst weather conditions.

My last 25 years have been mostly in the salt and I rarely go below a 9wt and have used up to a 19wt. 10-11wts I classify aa general purpose line weights for the salt.

As stated above, you select the line weight for what and when you will be throwing. I like to be able to throw anything I need to whenever I want to