I've had some times when I had trouble righting my Stealth with carbon mast. This was a day when there was too little wind to capsize, but I was fiddling with the angle of my mainsheet cleat and set it too low. First half-gust that came along and....

I don't doubt that the extra few kg of an alu mast do make a difference, but if you really want to be sure, carry a righting bag or some other system. I don't, but the places I sail typically have good rescue cover.

I've only ever capsized the Blade when there was enough wind to capsize, and have never had any trouble righting it (I'm about 85kg).

Rather predictably (as an F16 sailor) I'd recommend that you take a good look at the "proper" F16s (Stealh, Blade, Viper). With the possible exception of the Javelin, the F16s are significantly quicker than the other boats you mention, are designed to sail equally well 1-up or 2-up, and meet your weight requirements.

Paul