RE: Pince-nez comfort and security: Properly fitted and adjusted a pince-nez remains securely but comfortably attached to the bridge of the nose at all times. Opticians then were skilled in fitting.
Pince-nez was by far the most popular eyewear (especially rimless) during the 1880's to 1920 in the USA and much of Europe particularly with young people.
During World War I the USA army recommended a pince-nez because of the ease of wearing it under a gasmask.
College and High School YearBook photos of the era show that pince-nez was the most popular eyewear..many used no cords, chains or safety devices.

Moden rimless pince-nez readers are available from Debby Burk optical... debSpecs.com? Easy to adjust..there are 2 similar types..the newer with oval lenses are better..both sell for about 30 bucks and isinclude reading (plus lenses).
Only reliable info re: pince-nez is on Pince-nez Renaissance.. a blog with has all the accurate info re: pince-nez in great detail... this site/blog was created for those who wish to wear pince-nez eyeglasses
which, BTW were NEVER called spectacles.
There are from 25 to 75 pince-nez available on eBAY each day.. Check out pince-nez photos on flickr.com