stretch: W-50%, H-60%, polyamide 74%, elastane 26%, priced per metre
This super fine (90g/m2, but has good stretch) knicker weight fabric has a finished useable selvedge. This means that you actually utilise the selvedge at the top (waistband) of your knickers, so you can use a fine slim elastic and simply sandwich that in the seam without causing bulk. this is the sort of fabric now being used to create a very discrete knicker that doesn't show through tight clothing.
This also make a great powernet substitute for smaller sizes, or use below a lace or other stretch fabric to give sufficient strength for the bra wing in larger sizes.
Powernet is a mesh type fabric, which comes in different weights. The heavier the weight the stronger the stretch.