Man, this is starting to feel like it's never going to end. There are no many tiny tinzy winzy micro little details to adapt and huge amounts of variables to look out for. It's a slow and tedious work, but I'm getting there... baby steps!
Here's a significant advance in the project. Console/Computer systems filter in the tool bar. Initially I was going to merge that with the arcade systems but the idea was dropped. And no... EL will not include MAME software lists in those filters.