Never run 23mm, but here is the only flat I ever had with them on my 28mm
The screw actualy dimpled the rim , and locked up on the brake bridge. I wheelied to a stop on the front tire the best I could. A boot, and I was good to go.
Ran them for another couple hundred miles, then put them on my beater bike, where forty mile an hour decents on potholed pavement and flint road shredded it. The tread started coming off in big chunks, so I retired it and moved the front to the back where it does the most good. I ride thru dry county lines on rural roads where there are seas of broken glass from drivers throwing out whisky and beer bottles on the way back from wet county liquer runs, so they get a lot of abuse.
I was just considering getting another set in 23mm as a training tire. They ride like a brick, but I liked them ok.