Maybe you could put the bowlers into 5 catergories, say:
1877-1920 era 1
1921-1945 era 2
1946-1970 era 3
1970-1990 era 4
1990-2006 era 5
Then take two bowlers from each era, to give us a top ten. Then to rank the top ten, compare how far the selected bowlers rank in front of their contemporaries. eg from era one; Lohmann 140 Barnes 138 next best Spofforth 135.
This would give Lohmann a rating in the top ten of +5, and Barnes +3, But this would be fair because they are compared to the bowlers of their own era.
Is everyone confused now