I've been using International's Cruiser UNO Shell White for several seasons now. Keeps the boat clean afloat April to October - just a thin brown easily washed off slime when hauled out. However, it's recommended for not more than 25 knots, which is ok for me but maybe not for a Scorpion. I think Trilux stays on at higher speeds.
Trouble is, none of them seem to be properly white - Dover White is as grey as this little box I'm typing in, for instance. Shell white is better, but still greyish. After a while immersed they have a greenish tinge to them - copper salts, I suppose.
I have seen yachts with what seems to be 'proper' white a/f, but don't know who makes it. Be good to find out as I'm always a bit disappointed with the colour, though the a/f properties are good.