The z's are example strategies built by the Zorro team that you can use as they are with a few adjustments to your needs like margin, risk or excludes of some assets. Trade methods and algos, bar periods and other points you ask for are well described on http://zorro-project.com/manual/en/zsystems.htm but of course there is no source of the z's. Their trade methods are also well explained in the workshops of the Zorro manual.