These kind of things never really work if one takes a linear approach to aging. Inevitably you either end up with characters way older than TPTB would really like them to be, or you get ridiculously compressed stuff like the New 52 idea of 4 Robins in 5 years. Even if you stretch it out to 15-20 years there are at least 3, and arguably 4 generations of characters in the DCU just from the JLA on. It will just never work - even if you contrive some de-aging mechanism to keep the characters artificially young, their supporting casts and villains would age.
If these kinds of timelines and whatnot are to have any real value, the focus has to just be on ordering events rather than using them as a Bible for character ages. Crisis on Infinite Earths happened before Zero Hour, for example. Were there 3 years in between, 5, 9? It doesn’t really matter. There was a non-trivial period of time between them. Time passes in the DCU but characters don’t age in a linear way. Otherwise every time they told a Christmas story everyone would have to be a year older.