Here's a PDF of the instructions translated by Bob Wilcox.

https://www.dropbox.com/s/vywguytohc...ilcox.pdf?dl=0

I would pay a little extra attention to fin fastening, and the rudders do not need to be as large (in chord and length) as they are drawn here. This can be a source of flutter in the wrong place, wrong time, etc. been there...

Kelly