Monkeying with the geometry of the Scale Art loader bucket caused over-cam problems too, and I can tip the bucket too far back in a lower position as well... but I always keep the bucket level after it's emptied. I set the pressure to 17bar.
On the bucket, the distance between the connection points of the drag link & loader arms with the S/A was about 36mm (my memory is ?) and the Stahl WA500's bucket was less, I think it was 31mm. That wee bit of difference made a huge diffrenece in the dump radius, especially at lower height of the arms.
To correct the over-cam issue, I drilled & installed a bolt just below the drag link, so at full height of the arms & full dump of the bucket, the bolt stopped the drag link from over centering.
I saw Rcguy's Carson bucket at the St Louis meet in 2012 and measured the distance between the two points, I can't remember what the number was, but it was greater than the OEM Scale Art.
