Pre-any kind of “Crisis”, when the trope of a multiverse with Earths-One, Two, Three, etc. was firmly established:. At what point in the runs of the titles “Superman”, “Batman” and “Wonder Woman” do the stories stop taking place on Earth-Two, and begin taking place on Earth-One?
For “Flash”, “Green Lantern”, “Hawkman”, etc. there’s a clear demarcation. The original series were discontinued one by one. When the revamped titles began, they featured all-new origin stories and backgrounds for these characters. But Supes, Bats, Robin & Wonder Woman (not to mention a few also-rans such as Green Arrow & Aquaman) kept right on chugging from the late 30s/ early 40s with no breaks. Did the Powers That Be at DC Comics ever set a definite issue # for any of the series in which the swith from ‘golden age’ versions of the characters to ‘silver age’ versions took place?