Hi Striperick,
I follow your post as I am building my OB20. I have started 2 months ago and I am about o start planking some time the next 2 weeks.
I wouls like to ask you about the frames TF1 and TF2. In the plan it shows that are temporary i.e. they are marked with orange lines and the note says that orange line frames are temporary.
Have you removed these frames after finishing the planking and turning the boat upside down?
Manolis