Brand: Falcon Marine makes the Blade and the Falcon F16 and are located in the U.S. For heavier weights I would recommend the Falcon, the Blade is quick but can pitch pole upwind. AHPC makes a nice product that has an excellent race record, again well suited to heavier weights.

Your problem is you're shopping used. No Nacra F16's available on the used market, nor really many Falcons, so probably best bet will end up being a Viper.

Will need to contact a local beachcat sailor wherever the boat is if you want an independent review. That can be tough.

Finally, the F18 is really the modern equivalent of your 5.8, and worth considering if you'd like to race 2-up. You will be hard pressed to find a 50lb crew to race the F16 two up.