I have been doing some more thinking about the straps...
Never had a problem with my older BD. They are pretty much a thin piece of grossgrain.
The ones on the GG are even thinner, same result. No problem.
Then I used the new BD Contour and found that towards mid afternoon I would have to shift the position of the strap because it would be uncomfortable by then.
The new BD are a bit lighter than my old ones, so I don't think that weight is the problem or the only problem
As a comparison, the strap on the GG is similar to the one of the Stix (the top one) , no adjustment, but a bit thinner than the one of the BD in the middle.
Franco