What about this arrangement. Very simple.

Sorry this half got chopped off

Thanks for the reply...I really don't use throw blankets often (I live in Southwest FL) so I wouldn't leave a throw blanket out, but the pillow sizes you drew look like lumbar pillows which I'm not interested in. Mainly, I'm just not sure if I should be putting pillows in all 3 corners of the sofa or just 2? Most pics I see show large pillows in all 3 corners, but since I had to shorten the one run of my sectional, I wasn't sure if that would change the amount of pillows I should use?

I like odd numbers, so I would put two in the far corner of the longer side and one in the far corner of the shorter side and none in the middle. But that's just me.

Yes, I like that as well, the only issue is the far side of my sofa is against a wall under my art and in my head I just kept thinking since it’s under my art the pillow arrangement should be symmetrical underneath which would mean having the 2 pillow arrangement on each end of the far side of the sofa (which includes the corner section) 🤷🏻‍♂️

It’s really just personal preference, looks and function. I prefer 6-7 pillows on a sectional, no matter the shape, but that’s just me —

So that's interesting how your example pics you posted has them sizing down the front pillows by 4". I always saw them in 2" differences. So if you use a 22" pillow, you'd put a 20" in front of it. But 18" makes sense too as it would show off a bit more of a size difference. Hmmmm