I don’t think size matters , I’ve observed a pretty big one slowly being eaten over a couple days , one tentacle or two at a time until it’s gone. And well as weird as it is hopefully a couple aptasia survive and spread for a consistent food source - maybe put a couple in the sumpHe looks good.
As a cbb owner. I know this feeling. Grabbing infested rock. However. Some might be too big to ve of interest. Depends on your guy.
Mine will nip the large ones to death.