Gilo,

how are your sails compared to his. Same age and use? An old spi vs. a new spi can be a real killer if you are at the same skill level. Same with an old jib compared to a new jib. If the skill levels are not proportional, the sails dont matter

Was the telltales on the main and the jib all lifting at the same time and on both sails when you got a header or when you luffed going to windward?
Did you sail with the windward jib telltales streaming horizontally or with them lifting 45deg? How about the jib telltales on the F18?

Besides getting the trim right, there is a skill portion as well. E.g. building and keeping the virtual wind when going downwind and findind the sweet spot both upwind and downwind.

Any video from the "event"?
(seriously, if you have a camera, and I think you do (?), how about fixing it so we can see the telltales and sailtrim).