Die Tanzsammlung Dahlhoff is now available to download in PDF format, one file per book, from the internet archive:

Tanzsammlung Dahlhoff

If you want full-resolution, archive quality TIFF files then the best place to get them from is still the Staatsbibliothek zu Berlin site, but if you just want access to complete, usable, small-ish filesize PDFs then this is, as far as I know, the easiest place to find them. Viel Spaß damit!