I bought some 1/16" metal to make peeps for several of my rifles, my old eyes can't see sights anymore.
I made this one earlier out of 1/8" stock, it was a pain to bend, especially the bend to fit the curvature of the tang. Once on the rifle it works great.
I made a prototype out of the 1/16" thick metal, easy to bend but a little flimsy. I mounted it on a TC Hawken and found the 1/8" aperture is too large for the sight distance on the TC barrel, the entire rear sight and part of the barrel is visible through the peep. On the clunky sight above I use a much smaller aperture.
The problem with mounting this sight on a TC is the tang screw is a wood screw and too much tightening may strip the threads in the wood. On the sight above the tang bolt is screwed into the trigger place so I could tighten down the peep and keep it in place.