Ricardo, lot's of questions, I'll see what I can help you with. I've sailing a 5.5 Uni for 7 years now after spending many earlier years on a variety of Hobie Cats. The Uni is a great boat once you get it dialed in and then learn all the quirks of sailing with a single sail. Rick White's book on Cat sailing has an entire chapter dedicated to Uni's.

1. Mast...mine is carbon and very tunable with a combo of mast rake, spreader rake and wire tension. I prebend my mast to fit the luff curve of the sail and then leave it.

2. Rotator...I only force rotation downwind, approx. 90-100 degrees. Upwind, I only pull rotation in/out via the mainsail traveler. In extremely light air I will sometimes set the rotator upwind to force the sail shape I want.

3. Mainsail traveler....I started at the centerpoint of the traveler and then move in/out based upon wind conditions. Heavier winds further forward, lighter winds back from centerpoint. I indexed 1" increments on either side of the centerpoint and adjust from there.

4. Downhaul....add the incremented Hobie downhaul stickers on either side of your mast and index to a point on your sail for quick reference. I indexed mine to the downhaul grommet on the sail. Downhaul does have a big effect on a Uni's sail performance as you have no jib to help you along. Then, work on recording each of your optimum wind condition settings. Upwind, the Uni enjoys downhaul with the EP sails.

4. Rudder system....is just fine and yours probably needs to be rehabbed. I use 3mm nostretch yacht line with aluminum cleats. They never move under load. If your bungee is old/stretched, replace it. I threw away the silly clear tube and instead triple-loop and tie a 3mm yacht line around the bungee at the rudder and it works fine. If you do not have an adjustable crossbar, invest in one.

5. The Uni likes to be sailed on its toes...weight forward. Upwind, I am mostly at or ahead of the front crossbar. Downwind, pretty much the same until it starts blowing, then I start moving back. At 10mph and above a Uni can perform very well downwind.

6. You didn't mention sailshape and battens. I tossed the wimpy sandwich battens and replaced with tubular. Gives me much better sail shape performance and control.

7. Hobie's seem to like tons of mainsheet tension upwind. Break that habit as Uni's do not. Oversheet the main at any time and you will go slow.

8. Finally, the Uni is not a jib boat so there is a definite learning curve if you came off of TheMightyHobie18's.

Anyway, hope the above helps.

Sail fast, Tom G
Uni 5.5