I'll let others (more knowledgeable people) discuss your main sail trim, although it doesn't sound like a pinching issue to me, may be pre-bend related. With regards to going around the top mark in stronger winds I think we do the following (all happens on automatic):
1. Both move backwards on trapeze.
2. Crew eases main about 6 inches (at block). Cleats sheet and hands to me. He then goes in and starts preparing for rounding (boards up etc).
3. I take loose (cleated) main sheet in my Tiller hand and make my way to the transom foot strap.
4. As I pull away I ease an arm length of traveller.
5. Kite goes up
6. Crews comes aft
7. Traveller back up
8. Heat it up and go like (censored).
I generally stay on trap until the first Gybe and then the crew goes out.
I hope this helps.
We pull up the boards once the kite is up. The theory being that keep both of us out on the wire until the last second to keep upwind speed. Then I stay out on the wire and the crew goes in and pulls the tack, then pulls the spin halyard just as we are rounding. They then sheet the kite and go low side and pull that board, then high side for the other one. Then they will let off rotator, outhaul, downhaul.
This sequence means you aren't heating up with the kite quite as quickly, but you maximise upwind speed into the rounding. Plus it seems easier to pull up the boards on a fairly deep spinnaker course than when beating (more side loading on the board).
For what its worth that looks like the sequence people are using in the 'Catamaran Sport' video.
What do others do?