A question from someone in China -- why is this a minus when this other script uses a plus? -- prompted me to look at my SaVi simulations, and made me realise that their coverage properties could be improved.
So I wound up checking all my Ballard rosette simulations, and correcting the Celestri and GS-2 scripts, because with the phasing reversed coverage was clearly much improved in them. (Celestri lost a couple of small coverage gaps that had always bugged me and now appears more regular, while GS-2 increases in evened-out diversity from mostly-one-satellite-overhead to mostly-two-satellites-overhead.)
A look at Skybridge and @contact couldn't come up with any improvement, so those rosette scripts are unchanged. But with many eyes all bugs are shallow, eh?