For all those little silver squares, and to get the exact size you need, I would get a sheet or two of
sticky back art foam and either spray paint it silver, cut it into squares, and use the adhesive to stick it on and hold it in position then sew it down with a heavy black thread in a big needle.......
or you could stick the foam down to a piece of heavy duty aluminum foil, cut it into squares and sew them on with the heavy black thread and big needle.
It would be light weight and not pokey-jabby like studs or buttons......but if you go with studs or buttons or sequins be sure to check the sizes 7 and 8 mm of the two items posted is very small, 1/4 inch!
Could be accomplished many ways, any kind of foil or foil paper glued to anything else that would stiffen it, craft foam, plastic, cardboard......cut in to squares and sewed on.
Shylaah
