Note you just posted that SC video above and I haven't watched it yet, but I'll continue with my thought train.
So I am completely on board with this diagonal stance situation, or rather "straight and neutral" from the thrower's perspective and "closed to target" from the viewer's perspective.
The elite throwers I pretty much always see carry their momentum closed, like Simon, Paul, Eagle, Wiggins.
So in this video linked at 1:24 we get to watch Sexton, Simon, and Ulibarri throw full power drives. Simon runs from back right to front left to throw straight, this all fits. Nate and Paul both throw very in line, Paul more closed than Nate...but is this because they are both legit touring pro power but not elite power? I also posted this just to show the Ulibarri rear arm path I talked about in the last post as feeling natural after the battering ram drill.
https://youtu.be/YF7R1u0QZHM?t=84
Now in this video at 26:09 we get to watch McBeth and Seppo throw controlled golf shots 400+. Paul clearly uses the angles we've been talking about, and I think is the best low golf line player out there, without doubt top 3. Now Seppo has elite power, but he is one of the only guys I can think of in that modern category who strides basically in line with his throw. Why does this work for him? As well, if you slow down his throws his disc gets that old "skim the face" thing I'm so familiar with. Is this because he's not giving himself as much room to swing so the disc has to rise up a bit?
https://youtu.be/giqVr-_xAKI?t=1569
As well, is the super closed angle that I naturally found in the battering ram drill a bit exaggerated to what I would use with a disc?