Okay. So the 4th card on the riser but "use" the molex>sata adapter, and sata chain to PSU?
Double checking in case it melts again.
Strongly advise don't do this. Sata connectors are designed to safe for up to 4.5 amps. The risers could draw up to 6 amps especially using 1080ti. Much better to use 2 molex on one string. Each molex won't have a problem as each can do 11 amps. The only issue is the wire will get a little warm but not enough to be dangerous.
On paper you'r right, but from experience the specs are not very accurate.
I'm confident in saying that Molex can't handle 132 watts without getting very hot or even melting due to poor connectivity and +30°C at 11A is not exactly intenteded for 0-24 use. In a 30°C rig that's already 60°C which is just on the borderline of being too painful to touch for more than a few seconds.
In addiction, in my experience Sata is getting sold short; it can handle way more than 54 watts without even getting slightly warm.
Personally, I would much rather use each Sata port with a Sata to Molex cable at 60W then putting 2 cards on one Molex cable.