The default value is 500ms, Is there a tool to find the actual cluster offset? so that can make the value more precisly
You can find the measured offset in the prometheus metrics:
/_status/vars on each node.
The two fields are:
clock_offset_meannanos: mean offset with the rest of the cluster
clock_offset_stddevnanos: stddev with the rest of the cluster
This is calculated on each node and represents its offset relative to the rest of the cluster.