Hii Dan,
I am in a project where we are currently implementing Kronos integrated with Employee central and also implementing the Time off functionality within EC. We also have SAP cloud payroll which does the main part of the integration with Kronos though we do send Master data and Contract hours to Kronos from EC.
In addition to this we are using the Time evaluation functionality within SAP ECC to run time evaluation for generating the quotas and sending the balances back to EC so that it is available for the employees to book absences against them.
Will keep updating on our progress.
regards
Harris