I race my F16 (old Blade) solo all the time, but as said above, the windier it gets the harder you have to work and you get less competitive up wind against the two up boats. Whenever you are alone, you have to plan all your gibes and take downs well In advance as well as find a hole at C mark where you won't hit anyone while you are snuffing the spin, because you won't bed driving the boat for those 15 seconds, so make sure you have enough room before you drop the kite!

As far as weight, I was 185lbs. I have raced it two up at 320 and we were fast upwind in 15+, but slow when the wind dropped.

In the right wind conditions (single trap, 7-10kts) I would stay with the F18's upwind, and go faster downwind, same with the A cats, except they would be faster upwind but I'd pass them downwind.

Work on your spinnaker set up, the faster you can put it up and get it sheeted in, and the faster you can drop it and snuff it, the faster you can get back to driving the boat!