I would like to write about a speculative situation in the past and a possible result in the past. For example,
(1) If A did X, Y occurred.
(2) If A did X, Y could have occurred.
(3) If A did X, Y would have occurred.
(4) If A did X, Y might have occurred.
(5) If A did X, Y should have occurred.
We have no idea whether A did X or not, so I think example (3) is not appropriate. I would use example (1), if I am pretty certain that under this condition (If A did X), the main clause is true (Y occurred). But this is not the case. Even if the condition is true, there are multiple possibilities and Y is just one of them. So I can't use example (5). Do you think example (2) or (4) could convey the meaning I would like to express?