Automatically Build HLOD Proxy Meshes and Clusters with Command Line

Is it possible to automatically generate HLOD clusters and proxy meshes from the commandline (without perforce)?

Is it possible to automate the generation of proxy meshes and clusters and save them, before cooking and packaging the game?

Regarding cluster generation: Do you recommend to generate them semi-automatically in the editor, to have more control over the generated clusters and manipulate them if necessary?