Mike added foils to an existing pair of blades. The Stealth originally used the same foils as rudders and daggerboards (I think they were actually 49er rudders) - then most owners got the bigger R dagger boards and so had a spare pair of rudders!

I've never had a problem with rudders sticking. As Simon says, they don't kick up. But the big advantage is that you can sailo with them well up without the steering becoming really heavy - because you still have the correct profile of blade in the water.

I'm still not entirely convinced by the T foils though - in light conditions I'm sure they must crate more drag.