I have made 100's of these over my ceramic life. I have improved them ever time I can. For me since I fire to cone 11 so my buttons need to be able to withstand extreme temps. If you are doing raku or low fire or lower temps than 2400 in a reduction atmosphere you can use other clays and lesser (thinner) wires   For me stoneware clays will bloat sooner than white porcelain bodies in reduction. Not that bloating is a killjoy but it will shorten the life, as they will fall