I have a Campy SR head set with a split CR. I can't feel anything. I locate the split to the rear where the forces are minimal. Smooth as butter and a lot cheaper that buying a used headset for >$80 just for the CR!
I believe it happened upon installation in 1983. The difference between the ID and OD was creater than spec due to the paint overspray on the crown. I cleaned it up and reinstalled and still don't feel it.