I wanted to mount my V3 using the 1/4" x 20 screw receiver on the bottom of the V3. This screw attachment is accessed by removing the camera’s adjustable base. In picture No. 1, I drilled a 1/4" hole 1" from the end of the bracket and centered between its sides. This picture shows a 3/4" x 20 x 3/4" bolt with nut. The bolt head is not sawn-off here.
The base notch presents a weak element to the tightening action of the mounting screw. Relatively light tightening of the bolt could overcome the strength of the camera’s bottom. Also, the notch does not look good and is a place for bugs to move in, attracting spiders.
Picture 2 below shows a 3mm (1/8") shim plate that I cut from a piece of PVC plastic.
Picture 3 below shows how nicely the shim plate fits the camera.
Picture 4 below shows the camera attached to its mounting bracket.
The image below gives the dimensional details of the shim plate. Should you want to make one, you would select the thickness of the material to use.
Below is the link to the PDF file shown above.
If you should want to 3D print one or have it printed, below is the link to an STL file.
If you should want a 6mm or 9mm thick shim plate, below are their STL file links.
This last picture below shows how I lucked out in being able to determine the radii needed for the four corners of the shim plate. I happen to be old enough to select from a large assortment of pills and vitamins.