I owned an ASTIR CS77 for several years

I can offer you an article from D. Althaus in aerokurier 198? (pdf-file
in German, 200kb, with some pictures.

He says 35% from rear edge for Noppenband.
GROB had written to its customers 63% for Noppenband and 65% for
Zick-Zack from the front. Sorry i lost this letter but i still have the
drawing i made (pdf 8kb) when i placed my turbulator tapes.
Ruediger