I started experimenting with custom cog sets early this year.
My initial combo was 13-14-15-16-17-19-24.
I have friction shifters, and when I "erred" between the 24-19, I had a nasty "crunch, ping" sound. Going to a 19-23 made a huge difference. I don't get the "ping", and the 'crunch" is less severe.
Maybe I'm just shifting better since I'm not shivering?

IF you only use the 28 as a bailout gear AND shift GENTLY, you should be OK. Else, your "ping" may be a "PING"!

EDIT: I just remembered- My initial set up was 19-26 that "pinged". I only ran that a couple days before dropping the 26.