In this example file, all certificates are being replaced. The certificateDefaults sections contains your organizations' details.

{
  "replacementScope" : {
    "replaceEverything" : true
  },
  "certificateDefaults" : {
    "countryName" : "US",
    "stateOrProvinceName" : "California",
    "localityName" : "Palo Alto",
    "organizationName" : "VMWare Inc.",
    "organizationUnitName" : "VMware IT department",
    "keySize" : 4096
  }
}

The maximum keySize is 4096 bits.