Thanks guys for the responses, despite the fact that most are in response to the other person.
I've seen the shared chart with maximum wattages a few times and I know I'm not exceeding them. But here's the question:
Is the load evenly distributed across each cable, or is possible that the GPU may overdraw from one cable and not the other?
So if my 3080s are each hooked up with two 6+2s, and one part of that cable powers the riser, is it possible that the card will draw most of what it needs from just one cable, thus potentially overdrawing the cable?