I applaud your work sir and will continue to watch this thread with great interest!
From all the historical research to creating your own plans, it’s a tedious but rewarding process.
I too find tracing over and recreating ship plans rewarding and relaxing.
As for distortions in the entire process, I know a little bit about that subject.
Just as a rule of thumb, there will always be distortion due to all the steps in creating a printed image.
From artists drawing to:
Camera-film-plate-blanket-pressure-paper stretch-cutter-folding, back to a flatbed/drum scanner, it can’t be helped. You will almost never have a right angle to work from.
Do you use autocad in your day to day job?