I have also made the move to an F18 from an i20.

I've only got 2 days sailing on my C2 so far. 0-5 on the windspeed.

I felt our downwind speed was OK, about what I was expecting.

We really struggled upwind, we lacked height and speed very badly. The boat seemed very sluggish in the puffs, and seemed very slow to accelerate.

My upwind sails are 2010 vintage, but I think they have been heavily used in that time. I have a new jib on order.

Our mast rake was at the top of the plastic clip above the lower pintle. Rig tension was 110lbs, diamonds were at 450lbs.

With a crew weight of 350, what should should I start with as a baseline on spreaders and diamonds?

I could be just expecting way too much coming off of an overpowered i20.