Not sure where to go here. The great ERA guys like Robin Roberts ("Mechanics") and Paul Deringer (who?, Fanclub) have the worst RCERA's; while the better RCERA performers lag in ERA. Maybe Garland Braxton (Red Eagles) has an edge because of his 6-2 record?
If I had to choose right now I would go with Jack Chesbro (Miners). He has the best ERA of the five, is tied for the most wins, and easily has the most innings pitched. Ed Reulbach (Bears) looks great though, and this will come down to the next few starts.