Hi Dan,
thanks for the input!
My goal is to get it under 12kg (sorry, I will always be a metric guy) fully outfitted, with hatches and bulkheads – and also paint.
It's not for any kind of class, I haven't done any races so far, either.

The big difference really is that I try to build a very safe and stiff boat at the same time. Here's my layup:

4.5mm WRC throughout

Hull outside: 210g/m2 carbon/kevlar + 25g/m2 glass
Hull inside: 100g/m2 UD-carbon + 25g/m2 glass + carbon/kevlar hybrid in cockpit

Deck outside: 160g/m2 glass
Deck inside: 100g/m2 UD-carbon + 25g/m2 glass

…quite a lot!
The hull is so stiff I can hardly bend it. Of course I could go down in thickness, use a lot less fiber material etc. but stiffness also greatly improves performance of a boat and I'm looking for the sweet spot (which I believe is somewhere in that weight range).

Coming back to the bulkheads: If I can save the wood and just go for a very thin laminate that is able to flex a little, then I think this is the better option…

Since this will also be a boat for touring to some extend I will still add hatches (I bough some small rectangular magnets this time) and bungees. In fact it looks like I will have to add 3 hatches, 2 for storage, one for the rudder.
Will see how it goes next week, time is pressing as we still want to take it to the Adirondacks and Maine this summer…

Best, Matt