Looks like if you use Schoopy’s development image, and follow my steps on that thread, then go into /Database/linux-18.104.22.168, and run the command “make menuconfig”, in there, there are some ipv6 options that are disabled, you can enable them, exit, and save the config.
I have not tested it yet though, just found that those options are there. Still looking around on how to shape the traffic though, perhaps with tc somehow, rather than an iptables rule.
I see that the iptables module “ipmark”, which is not part of ZS modules, states some things about ipv6 shaping. Hope this helps