i attach tests that Franz made, let me know what you think
actually we have tested two solutions:
a)Thicker sheet for gondola tops: the solution is good, they tend to be more straight. We have worked two coils with good results but we had an enormous amount of coils stocked that have to be finished. The problem is that the cost of the component will raise a bit (0,8 mm vs 1,0 mm)
b)In the last two months we have started to over bend the tops and, as you have said, they behave better with respect to the sliding of the top.
If you think that solution b may be sufficient then we may stop here. Eventually we may follow also solution a.