Currently our mainnet nodes have a

Period = "30s"
CatchupPeriod = "15s"

The default testnet has

Period = "25s"
CatchupPeriod = "15s"

The unchained-3s testnet has:

Period = "3s"
CatchupPeriod = "0s"

But the information about the CatchupPeriod is not provided on the /info endpoint, so this is not a very easy to access information.

Furthermore, the CatchupPeriod is not part of the group hash, and every node could change it manually in its group file, so this really can be variable.