If it were me (and it has been me in the past), I would take the entire area of rust and cut it out. For areas with surface rust, I would grind it off until it was at bare metal and if it was deep, I would go deep until it was 100% not visible unless of course you are looking for a temporary fix. It is the only long term solution--get rid of it completely. Converters will kill the surface for sure. And in light rust conditions, it works pretty darn well and I have/do use it. But that is not what you show--what you show will continue to spread. If it is light surface rust, converter and sealer will do very well for a long time. Potentially permanent. But I have never seen rust stop when it is as advanced as yours. It may take a little time for it to work around the converter and patch, but it is growing like cancer. Remove it or it spreads.