Slow, clean and heavy. Make it easy I will try.
Wing needs to produce required lift, which it will do, I think Slow holds the simple key, wing moving slow allows more time for higher pressure air under the wing to find lower pressure air on top of the wing.
An easy to think of it could be, keep slowing the wing to zero speed and have magic higher pressure air under the wing, this hi pressure air would have all the time in the world to slip over the wing tip and find the low px air.
Well at least that's what I though I read many many years ago.
Anyone have an easy way to explaine why heavy aircraft glide further than lighter aircraft ? (engines switched off)