As skipglo says, need to test bullet for accuracy first; THEN a BC conversion that's reasonably "close" will provide adequate dial ups to 'actually shoot the distances to his 600 yard request'. From that work one can end up with actual drops and decide whether to use a door card or request scope manufacturer to do custom turret.
Not all that hard; just gonna take some time to confirm actual field results. ( that really needs to be done even when a manufacturer tells you they can build a turret without actual drops and off bullet BC, elevation, temp and velocity assumptions)
IMO
Good luck.