[Formulajones]

That doesn't explain or show what I'm asking. That appears to be explaining how the air and fuel mix and the relationships between air bleed and fuel bleed sizes, but mentions nothing about why some want the IFR up high where the air enters as apposed to down low and then having that fuel travel up before it is emulsified. The 2 links before you posted showed no bases for their reasoning either, they just basically say this is how it should be without going into detail as to why.

From what I've done here, I can't detect any discernable difference either way.

I'm all ears.