Sailing a Sunfish in steady 25-30 is a GAS! SSmuelders had it right! Drop that gooseneck WAY back, consider putting on an old recreational sail (smaller and flatter than the racing sail), make sure your daggerboard retainer is in good shape, and head on out! Laser sailors in these conditions spend their time swimming. Sunfish sailors in these conditions spend their time FLYING! Your major challenge will be tacking. You need to develop the skill to be going full speed, jam the tiller over, jump across, sheet in rapidly, jerk the tiller to fall off and start moving forward (or preferably keep moving forward) so you don't lose way.
If you lose way you will likely end up in irons, and you will never have gone backwards as quickly as you will in this situation. It's a little frightening the first time, but don't fret. After some practice you will develop the skill of putting the tiller over to the side to which you want the boat to turn. After it turns fairly far, you need to jerk on the tiller a number of times the other way as you sheet in quickly, and get the boat moving forward with steerage before it starts to back up again. Once you've done it enough times you'll develop the skill and will develop the confidence to know it's just a learning situation.
If you can, launch, depart and land from a protected site. IT'S FUN!!
Good luck!