Hei, building a Widebody myself and it will be about 23ft. The hull looks very nice, good proportions and one doesn't see the extra length.
What I would suggest is to get maximum length out of your building materials, don't remember any detailed measurements, but using full length ply for the bottom and sides will give you about 23ft.
Less scrap and a bigger fish deck.
I have also started to design a shortened cuddy and smaller cabin. Mock- up with clamps looked nice, but be advised that the original design will not work out. You will be working further forward and will have to handle lots of curvatures.
I never liked the box-like cuddy design, so I think it is worth the extra work. But installing side windows is another problem. And all the dimensions will be completely different, the book just giving you a general idea.
Would love to have drawings or pictures, but that will have to wait, summer trip with my kids and just my phone.
Peter