Help: Load custom avatar offline or edit preset models

Hi

I am building an app that is required to be offline. I am using the meta avatar sdk, but I would need to have customised avatars inside the app. I am trying to edit the preset models inside the SDK to have some looking like my users but I can't find anyway to do so, any suggestions ?

Otherwise, is it possible to save custom avatar models from the quest editor ? Then I could add them to the preset folder.

Thanks in advance !