Wow I'm such an idiot.
Perf to 4x molex, yup there it is. I was so eager to get it set up I ... honestly, I don't know how I missed it. I've looked through that bag like 10 times.
Are you using three molex's for three of the risers and then the fourth for the add2psu?
My risers have 6 pin inputs and 6 pin to sata adapters, so I use sata power cables mainly, for them. The molex is only used to connect the PSUs.