I have no chart for adjusting the backfocus. Can I use any suitable chart or was the included one optimized for this particular camera/lens?

I have the Canon HD KH19x6.7 lens (VCL-719BXS).

Any tips for a link where to download and print a chart?

Hi Joachim. You need a so-called 'Siemens Star' to do this accurately. You can download and print one (on semi-glossy or matte, high-quality paper preferably) )from here:
http://www.temple.edu/sct/fma/pdf/filmmaking/manuals/SiemensFocusStar.pdf

This is a really good chart Joachim and I use this all the time with my Sony F350.