Wrong
- avoid head on approach in both following and head seas, use a more angled line, How much of an angle and in what swell direction?
Yes.
- trimming the motor on one side lifts the nose of the opposing hull, This seems a little counter intuitive to me, is it correct?
Yes that works but you will have to get a 'feel' for it.
- Trim the motor up on the side the swell is coming from, lean slightly into the waves.
That works to a point but when you're forced to slow down because it's too rough they turn into dogs.
- Keep speed up in rough conditions to keep air in the tunnel, slowing down is a big nono
(Worse than monos)
I had a super trim sensitive 16' Sharkcat for 15 Years and the only thing I never managed to do was roll it over but I came close a few times.
Take it easy & do a lot of experimenting along the way, you're still going to get caught out but they're very forgiving after the scare the crap out of you.
Popcorn anyone?