I had the same thoughts.
I have searched on and off for the past week for a suitable screw.
The only one that looks promising at all is one sold for a steadicam. $5 a piece.
And I have no idea of the actual dimensions yet.
IMO this is too expensive anyway.
A custom screw would add too much cost.
The countersunk screw design is done and I am not happy with it.
The design would require a washer between the clip and light and available washers do not fit correctly.
Also, the head of the screw is large enough to cause concern of the durability of the remaining material of the clip.
The only way this style would be done is with a buttonhead screw, and washer, and the light would no longer tailstand.
I am at the point where I have spent a lot of time on this clip and must make a choice.
I will build a clip that is similar to the D10 clip if you guys want them.
I see no other way to offer a quality clip for a reasonable price.
Since the manufacturer refuses to make this style, I will consider it.
If a member that is affiliated with Nitecore has a problem with this, please feel free to contact me.