RE: 88 or 99 flare
I think the two recommendations above for the 88 are quite solid. At your present weight, the larger 99 Flare will require too much effort to advance your goals, especially given the sail sizes that you have targeted. It's not that you couldn't potentially throw around the 99, it would just take much more input and you really don't need the extra width and volume.
However, it very likely that your weight will grow significantly as you mature. If your intent to have the board for 3-5 years, and it's important to buy a board that you can grow into, maybe a 99 choice has some merit in the long run. I guess you need to decide whether you want to be hampered in the near future using a board that would be less than ideal for your present size.