One way I have found to quickly test how comfortable a saddle will be is to ride on flat route continuously for an hour or more at a tempo pace and constant RPM without moving out of the saddle for this test period.
If your hurting at the end of this test with one saddle, but with another one it is mildly uncomfortable it might be an indication which saddle should be used for a longer test ride.
This will not replace a longer evaluation say a 200 klm brevet, but it will give you an initial evaluation.