Messages in iCloud, different retentions, different devices

If I have Messages in iCloud turned on for all my devices (iPhone, iPad and Mac), can I have different retention settings on the different devices? If I set my iPad to only keep 30 days, when it removes old messages, will they also be removed from the other devices? If I set the iPad to 30 days and then later decide to keep a year, will it redownload older messages from the cloud? If I set all my devices to keep only 1 year, will older messages be removed from iCloud or could I change 1 device back to keep forever and get the older messages back?