first thing is a guide, or pilot, bore, 0.25" is good. drill no further, obviously, than the main m8 tap bore goes. i suggest falling slightly short, you can drill further as you wish with the appropriate diameter bit for an m8 tappping. if you are using a machine drill press or multi axis machine with proper reaching heads then man you have it easy. if you do it by using your hands, then you will have to measure the angle as close that you can. i forgot what i used, i can check tomorrow perhaps. then it is simply a matter f setting up a fixed and angled drill point with a counterbore bit or endmill. for the depth of the recess for the squirter, allow no more than 7mm and no less than 6.5mm. measure from the bottom of the recess to the edge of the remaining or untouched "slope". then it is the matter of drilling the minor diameter bit appropriate for an m8 tap. after that the next size, which is the largest diameter, for the tight clearance for the pressure flow bolt f the squirter system. then tap. remember that the recess for the squirter "block" should be flat and as smooth as possible.
last bit, and most important: do not **** up.
