Sorry, didn't realize there was write-up to download.
I have virtually every manual put out: Haynes (2), Chilton, Clymer, 70, 72, 74 FSM, a couple for pre-67 Opels, an Opel/Solex repair training and modification book, and others I don't remember. It has been very helpful having this stuff to compare and cross-reference as not every book has all the info and some of the later ones include revisions.
There are two other books that are of unbelievable help, if you can possibly find them. When I bought my second (and third) GTs, the owner also had the GM exploded parts book for 68-75 Opels, 64-67+ 68-75 Parts reference books (the one with every little part listed by part number and application, which cross references with the exploded diagram book). I cannot tell you how much help those two books have been. And I have no idea what they would be valued at.