I have experienced a problem with flashback and the solution is to recreate the control file (the error was ORA-01207).
So to do this I tried
alter database backup controlfile to trace as '/tmp/trace.sql';
This creates a file that instructs one to either use set one or set two. i.e. with or without resetlogs.
How does one determine what set is the most applicable? Is there any tests that one needs to perform to find out?