Wouter,
The 100 hours is for standard PT.
When James and I built we wanted to try some things a bit different. Yet produce a boat that still measaured in.

So when talking 100 hours:-
The panels are not glassed.
Only one deck stringer between the beams and centre case.
No bulkheads.
The chainplates are normally bolted on after the hulls are built.
Removing the centre case will save maybe 3 or 4 hours.

Keep it simple.