Having had this piece break often (the little "claws" would snap off) I just rotated it to change the direction of the layers, and made a flat bottom. The "back" is also a bit thicker, since I've had it break there as well.
It doesn't look quite as neat with the flat underside, but it holds together better.
3d model print parameters
Just print it as-is, 1.2mm shell thickness gives good strength....