I like this strap a lot, and the leather is super high-quality. It is very stiff out of the box, but below I give you my 2 cents about how to soften it quickly.
There are a couple of (secondary) issues that I don't like. one is just aesthetic, that is the blunt end of the back strap -which could be solved, easily. The second is more relevant, as the edges of the strap are quite sharp. Not sharp that one could cut, but sharp enough to feel uncomfortable at the neck. I found myself pushing the strap aside several times while playing. But the good news is: it could be fixed too!
For the rest, is a very good strap that doesn't slip (+1) and will last a lifetime.
Moreover, the wrinkles give the strap that road-worn look that we like so much when it comes to leather stuff. Needless to say, it holds the Schaller strap lock system perfectly, given that you tighten the back one tilted (the degree depends on your playing style, I suggest you leave the button loose, wear your instrument, and then tighten it).
Fixies
To solve the leather-related stiffness when new, just use some oil/wax product (there's a huge choice: from food greases, like the coconut fat to wooden boards care products. Either way, be sure that the ointment is food-grade: you don't want some toxic to get on your skin, right?) and bask the strap in the direct sun for a day or two. Repeat some 2-3 times and the leather will get much softer.
For the blunt end issue, one could cut it round with a very large and sharp scissor: there's room for cutting even if you're playing bass low, using the last hole.
The sharp edges could also be fixed, but this fix needs some patience and skill. Take a Dremel -or similar- mount a rather rough sanding stone and AT LOW SPEED FIRST engage one edge with a 45° angle. Be soft-touch and try to move at constant speed. Again, you do not want to remove too much material, as the stitches are close, you just want to make the sharp edge a little fuzzier. No need telling that this will also contribute to the road-worn look. I suggest to limit this treatment the the two edges (upper and lower) on the neck side only, and only to the portion of strap that is close to your neck in playing position, because the wear of a heavily used gear is never homogeneous.
Cheers!
