Why would you need to do this out of curiosity? The default watch faces (not the CIQ ones) use a special dedicated low power processor so having the second hand does not have any impact (or very minimal) on battery. Although much less of of worry with the later watches and later CIQ versions, the issue has been with the power drain of the CIQ watchfaces as these use the main processor so constantly calculating and re drawing the second hand had a noticeable impact on battery life.
Yes, agreed; on the Fenix 3, the standby battery life was measurably better using a built-in digital watch face with no seconds display than with a built-in analog face, but on the 5 series there is no difference.
