yuguzhai qinpu - what's wrong with it?

The yuguzhai and its author Zhu Fengjie are a bit of a mystery.   Probably the yuguzhai is a secret handbook in the "kongfu" sense - a few copies were made (not very many out there apparently) and given away to friends and students.   (I'm talking about the Yuguzhai itself and not its bastard stepson Qinxuerumen).  The section on qin-making does not necessarily represent a good approach or the common approach at the time.   It is possible that Zhu Fengjie did not build qin but had someone do it for him.   Here are a few grains of salt to keep in mind:

1. The section on string making as pointed out by Huang Shuzhi aka Wong Shuchee is wrong in the counts for "threads".   Apparently the counts in the book itself are based on the cycle of 5th.  In reality they are more of of a linear decrease from big to small.
2. The section on making the curvature of the top gives a method that is I suspect too simple.  The resulting top is more or less flat with curved sides.   I am referring to the use of the "forms", drilling down, and getting rid of the drilled sections on the side.   Zeng Chengwei just uses a plane and makes the wood chips fly.   I draw a circular form on the end (the nut side) and use a very big plane and a long meterstick to make sure I am doing things "straight".  In general the top should have more of a curve. 
3. It doesn't mention (I believe) the necessary concave curve (see this blog) on the top.   
4. The bottom board seems to be too thick and is never hollowed out in the real world.  You might do this though if you can't find a top board (on the order of 1 1/2 inches) that is thick enough.  
5. The lacquering section is over-simplified but on the other hand lacquering is non-trivial and takes a great deal of time and patience.  
6. Keep in mind the book is talking about building qin in S. China courtesy of 1850 or so.  Modern methods may vary (including finding wood ...)