Some good visuals, Ladies!!
That being said, I haven't been convinced yet that it makes a huge difference. Maybe? my quilt sandwiches are not thick enough that there is a difference there?
Here's what I do ...
Cut binding. "Clump" it on the ironing board, spraying the clump with Best Press. Then fold and press along the length. Depending on how long the cut binding is, then every once in awhile I respray the clump. IOW not every inch of the binding gets the benefit, but mostly it does.
Like you JanieW, I do not pin the binding to the quilt, as I machine sew it onto the front. One more step before I do the hand stitching. JanieW you will remember I lost you on this one before! I do a long machine basting stitch around the quilt, stitching the raw edge of the binding to the quilt edge, to hold all in place. This stitching will be hidden, once the binding is flipped over and sewn in place. (Better explanation this time??)
Then I flip the binding to the back and hand sew. I use those hair barrette type clips to hold in place and only pin at the corners. I keep it pulled around the sandwich edge, so I have a good tight/filled binding and watch the corners are squared up nicely before hand stitching. Ladder stitch all the way, for me!!
I don't have any problems with any bulk making the fold to not want to lay where the pressed fold is. Like I said at the start, maybe I don't have a thick enough sandwich to distort it? I do use standard battings of assorted types/content.
The important thing ... do what works for YOU!!