I dont have any magnet, they seem to calibrate based on distance set and then rpeat that distance in either direction to open or close.
The curtains are short and light, they are cheap and grommet style. Not any fancy fabric weight. Think kids room cartoon animal curtains.
Tbh I am giving up on them they are clunky and not a great addition. I can't be sure they will either open or close. And they are louder than I thought