I don't recall ever reading the visions of St. Margaret Mary so I can't say either way. No, I do not practice the particular devotion to the Sacred Heart. I think that ecclesiastically-approved pilgrimages and acts of penitence are commendable, and that Our Lady appeared to St. Juan Diego.
I don't feel obliged to answer any more of these questions, so I'm not going to respond if you ask more of them.
You were never obliged to answer any of them, I didn't think you would get so touchy about it. Most people that I know that practice devotions like to share their beliefs and practices with others, that's usually how people learn about them now since they are not fostered in many families or by the parish priests.