This size is the easiest to use weight performance. The difficulty is that the flat head screws that can be used to fix this size are not sold quickly. Since M8's flat head screws are not common, I used Sems (pot) without a help without having a home center.
There is no problem at all. I just wanted to install the IS-8 type with M6 screw. For the thing which seems to be the IS - 8 equivalent article of the home center, since the installation hole was small, it used φ6 drill to enlarge the hole.