Oh, it really varies. I even switch it up myself. I would never use anything less than 2 1/2 myself. A lot of my customers prefer the 2 1/2, but that's mainly because that's what they're used to. Some change their minds when I tell them that a 3" solid leather strap isn't going to dig into your shoulder like the cheap cloth ones do. As a tooler, I usually prefer 3" because it gives me a lot more room to work with for artwork
Here's a good article that Paul Burnett posted here which explains what I was talking about (page 2). Also, I had noticed after the fact that there's a few spots that your line flares out as it goes underneath. This happens a lot when you bevel the line that goes under first and then to the one that crosses. It just gets squished down into that flare. Try to make sure you do your crossing line first and then come back and do the line that goes under. If you can't avoid it, come back and square things back up one more time.
http://leatherworker...showtopic=19995