i´m asking because i will give this a try http://www.isa-racing.com/product_info.php/info/p7040_Speed-Bleeder-Entluefterschrauben.html
these nipples are called speedbleeders. they´re easy to use for bleeding one man show.
what i know the bleed nipple of the clutch slave cylinder is the same like standart brake caliper one. as you said M8 ones.