As there were many discussions about the thickness of the keel and keelson I would like to summarize my findings about this.
I guess this thread for tips is the right place to post it.
Thanks also to Tobias who was the perfect sparring partner for some discussions and to make me think about it.
All dimensions below are valid for 1/36 scale.
As a result I consider the 6.95 mm shown in Adrian's book as wrong, 6.75 mm as final thickness (width) of the keel would be correct.
Starting point is the chapter "Scantlings of the wooden framing" at the end of the monograph:
Please note also, that the keelson has at the stern a separate part (rear keelson in below image), marked as "k" on plan 2. This part of the keelson is less wide (6.75 mm) compared to the rest of the keelson (7.5 mm). I came to the 6.75 mm for this part by comparing it with the width of the keel. Both parts are showing the same width in my point of view. I checked it with caliper and magnifying glasses.
Note: The same is valid for part "j" at the front.
So both ends of the keelson (k and j) are only 6.75 mm wide and not 7.5 as the rest of the keelson.
Here are some measurements/dimensions of the single parts:
That this rear and front part of the keelson is less wide can also be seen on different parts of different plans. Only shown for the rear part in the following images.
So in a nutshell:
Width keel: 6.75 mm
Width keelson: 7.50 mm
Width rear and front part of the keelson: 6.75 mm
I hope this helps and was not too confusing.