Purging is in grain now. You can exclude whitelist from purge. When I put in WoT, you could set event acceptance to your WoT and purging to a week and it will keep all the whitelisted npub notes and purge the WoT notes for the set time frame. This is my plan to get all the notes from people I follow on a weekly basis but only permanently store my whitelisted keys notes. Then there will be a backup relay config which you could set to the blastr and blast out all events grain recieves. Maximum reach minimal storage. Of course, if wheat is not in their list, you're still hoping some other relay will send your followings notes to it. I would need some function to try to fetch your WoT notes and it maybe only use one relay then.