for what it's worth, the apertures in my EyePal patches seem to be both very slightly smaller and very slightly larger than 1/16". The pistol/archery patch is close to but slightly larger than 1/16" (but smaller than 5/64). While the patch for rifle is smaller than 1/16.
I did my guesstimate measurements using drill bit shanks. Unfortunately I do not have any bits smaller than 1/16.
Although I could (and have) used one size for both pistol and rifle, the clarity is certainly better when using the correct sized aperture for each (rifle/pistol).
Searching the internet I did find a 1.25MM pin hole punch (very close to 3/64"). http://www.amazon.com/Beadsmith-Meta.../dp/B005P1UEK0.
Also found a 1.8MM punch which would be slightly smaller than 5/64". http://www.amazon.com/EURO-PLR-133-5.../dp/B0058ECKR4
If I were going to try a one size fits all, I would go with the 1.5MM (very close to 1/16") http://www.amazon.com/Beadsmith-Meta...pin+hole+punch
added: after further review I am not certain these punches will work. in all cases they describe punching thru metal. no where was plastic or vinyl mentioned. so I do not know if they will cut a clean hole. thru previous experimentation anything but a perfectly clean round hole will create some distortion in areas of your field of view