Thanks a lot for your comments!
The sunburst was actually just an experiment, since I was going to keep this one for myself I have this $25 airbrush setup to spray resolene on larger areas and I always had in mind to try something like fading edges or gradients but never found a suitable project. Now I bought a bass with a pretty bright paint job and I needed something nicer than what I already had. I was surprised at how well this new one turned out, something I didn't expect was that the stamps would not pick up the sprayed paint very well so the red still shines through.
I keep the flower natural by putting on several coats of a resist / clear lacquer before using antique. I also used this on the coloured parts of the design such as the green leaves and the white skull.
The foam is from a company that produces medical pillows and matresses, I think it is widely available. I used some other types of foam in other straps but I found that, besides being more comfortable, it retains its shape underneath the lining best. Also, I have the feeling that after a while the foam sort of takes the shape of your shoulder - my other strap became more comfortable over time (which is nice since I had a nasty collarbone injury).