Nice tutorial.
If one is planning to make several potholders of the same fabric, one could quilt all the fabric at one time and then cut them to size.
When I was making potholders last winter, I had trouble with the layers shifting a little bit. I trimmed them to even the edges, but I think cutting them out after quilting would have been more efficient.
I like the idea of using an old towel. It never occurred to me to use terry.
I've used one layer of warm n natural with one layer of the stuff with the shiny in in - tinsel brite? Worked fairly well. I was making round pot holders and I had some trouble with shifting while I was quilting them. And I have a walking foot.
The other thing I tried - and it worked well - was to use the padding for tables. PRESHRINK it first. I bought a yard and after I washed and dried it, I had less than 24 inches.