It seems there is a lot of interest in running rigs again over the last couple of months.
Not before time either IMO. I've never liked the clip idea having found them to be pretty unreliable.
As for lead core, well despite the comics having pushed its use for the last few years, using it has never struck me as being very safe.
Just in terms of using running rigs in weedy situations, try tying the lead to the running ring, using 2 or 3lb bs line. It doesn't take much for the lead to break free, especially in dense weed