however silly this question might seem, there is a legitimate reason behind it... I would like to go back to Sierra on my iMac. So after creating a bootable Sierra installer I intend to wipe the drive, install Sierra and restore from a Time Machine snapshot. So I would like it to be the latest Sierra snapshot possible... Is there any way of finding out which one it is? I don't remember when exactly I installed High Sierra and want to avoid guessing blindly.
P.S. I take it is possible to restore from daily Time Machine snapshots or do I need a special backup that I should have done in the past especially for this case?