how to set "Project Picker" custom field (with scriptrunner)

[Renni Verho]

We have escalation script which were working ok, but now after one custom field is set as required we need to fill it f it is empty. 

custom field type is Project Picker and I tried to set values by script 

def customFieldManager = ComponentAccessor.getCustomFieldManager()
def customField = customFieldManager.getCustomFieldObjectByName("field name") // name of CF

if (!customField.getValue(issue)) {
def optionsManager = ComponentAccessor.getOptionsManager()
def fieldConfig = customField.getRelevantConfig(issue)
def option = optionsManager.getOptions(fieldConfig).find { it.value == 'Project: ACR' } // value of option

issueInputParameters.addCustomFieldValue(customField.id, option.optionId as String)
}

by some reason I cannot get match to project in def option. 

what would be correct way to set project picker field ?