Comparing Zoom Top with Fanta Bale the astute jeff Holland came up with the following comment. Jeff Holland: The problem comparing different eras, is also borne out with different systems, for example there was no Group racing, but you had the Age, Sprint and Distance Classics and Feature races, many with gruelling lead-ups. On Fanta Bale, from what I saw, Mercia Bale would beat her over any distance.
Here is a bit about Mercia Bale.