I did note that the Bleacher report issued a list of clay-court GOATs recently:
Here is that list distilled for the men:
It mostly corresponds to our list, but with a two serious oversights, specifically Rosewall and Wilding. As is well-known on here, Wilding was, I believe, entirely undefeated on clay for a number of years.
I submit that Rosewall was an excellent clay-courter, with many clay-court wins to his name.