This is another inmate's idea and it worked well for me. I didn't like repeatedly using steel screws into alum on the oil filter cover. The solution is studs.
First thing I noticed is that the threaded holes in the clutch cover are deeper than the stock bolts, by about 6mm. What looks like a longer bolt, is actually a stud with a nut. The bottom one is the stock Zuki bolt.
This shows all 3 studs (cut/ground to length) screwed into the entire depth available, with the ground ends exposed. Sorry about the fuzzy pic, the camera was smarter than me when I took this pic.
After getting the length right, I flipped the studs to show the factory ends, drowned in Loctite (wiped off excess), and left to dry. DO NOT tighten the studs very tight, that will introduce an unwanted stress into the case bosses. The Loctite will take care of that.
and strong and steel on steel.