Basically what the other people said but I would put T-foil rudders on the top of my listing.

Even relatively small foils will take care of the last remaining issue with F16's; going downwind in a big blow.

Hey Rolf, you guys should really consider doing T-foil rudders.

Will make the rudder board design alot simpler as well as you would no longer need a taper at the end. Basically, you can make a 0.95 mtr. long prismatic rudderblade (square side profile) then cut the bottom 30 cm off and screw is to the bottom of the 65 cm long rudderboard made from the other section.. By using two screws and the natural curvature of (the top) of the T-foil you can fine-tune the angle of attack of the T-foil in a range of -4 to +4 degrees. Once the right angle is found you'll just fill up the openings with resin and filler.

It will be a relatively low aspect T-foil (aspect ratio of 2) but at least this one won't stall easily. Added drag is less then 2 kg on the total (when doing 12 knots of speed).

Wouter