Any inserter even first black inserter has option to read hand contents - your mod allows to filter items and filter items for left and right sides
Can you add ability to connect loader by circuit wires?
I would be very grateful
You should be able to attach a belt, set it to read whole belt, and that should just work.
I can't add circuit support like that because it's not naively supported by the engine, so it'd need to be added by the developers before I can do that