I aim for about 1mm thick for the finished version. The two different batches of my "S" have been slightly differing thicknesses around .040 and I think .045. But with after brazing finishing and how well the bending about the HT went (actually bent in a female form with a male form pressing down) the vertical portions of the "S" don't really get bent/curve. So these will be filed a bit to mimic the rest of the curved face. I find that how well one maintains the flat face of the badge makes the thickness look one way or the other. Keeping the edges of similar thickness and not "rounding off" the face towards the edges makes the badge look more crisp. My first SS "S" was hand cut fron .049+ tube (took forever) and ended up with a more bulbus look after a lot of edge filing/sanding. Not a bad look for the fillet frame it found but not what a lugged frame wanted.

As to the bendability of SS plate. The .040+ thickness I've used is no problem. There are no creases or corners, in the bending, so no real chance to crack or have less the square corners. But if a badge were to have a relief or carved surface it would likely be thicker and the thick/thin differences might well provide an uneven bending. For this reason if major surface texture is wanted consider carving from a tube of casting. Andy