I have grown a lot of succulents but never a conophytum. I've generally stayed away from the winter growing mesembs. Just a matter of choice. Your plants look great Alain. Plump and healthy. I didn't realize the old flowers made such a mess. Very nice group of conos.
It is probably sensible to avoid winter growing Mesembs. I have always had two or three Conos. but a few years ago John Pilbeam gave me some, then I got Steve Hammer's Dumpling book and Terry Smale sells nice plants at the Mesemb. event and I now have quite a few.Cono. flowers are often bigger than the bodies and when they finish they stick together. If I get time I like to remove the skins of the old bodies each year.