" 9 string qin" : transforming 7 strings to 9 strings on an extg wood qin

"Large Handscroll" lighter color one

"xyz" with string full bridge on left

 "xyz" w full bridge, bottom right

Advantage of doing alteration using an existing qin is that its reversible.  

You could always go back to 7 strings, if you did not re-drill positions of the holes.
That is why I think the Large Handscroll is a better candidate for the transformation.
I have two existing wood qins that could be used to add strings to.
Eventually, one of them maybe used to change into a 9 string qin
I have made them myself and they both have v gd sounds
1// Large handscroll, this one has a wider body with a bridge that can include 2 extra strings on the end, although it is at the limits
2//  xyz qin in Shan wood (fir), this one has a full flush edge to edge bridge, so all the holes could be re-distributed to make room for 2 more strings
Now, whats the advantage of having 9 strings, is it really gd for a new idiom?
I listen to the sound track on John Thompsons site,  it is a v beautiful tune.

What to do?

Making a new, specially designed for 9 string qin w 3D printing would be interesting, maybe to make it the same model as one of the two above so we could compare?

First get a 3D printer and we can go on.  

3D printing is also a repeatable method, more or less, even though each print is - especially if you inspect it on a microscopic scale - still an original, because due to temperature and time conditions, each output would be unique too.

We could eventually print w customised filaments making the embryo w different porosity depending on the settings of the print.