The problem is that if the framework follows the main estimates it's kind of backwards. The timing is reversed. A framework doesn't do much good in framing issues if it comes after the estimates, so to my mind the key issue is that....
Let's work backwards. When do the estimates have to be tabled in order for Parliament to complete its work before the start of the financial year? That's the key marker.
Working back from that, you ask the second question: how much time is needed between the framework and the estimates for government to complete its budget work? I would estimate that is approximately one to two months, because a lot of the work will already have been done during the framework stage. Then, building back from that, you would have the framework.