MakerBot Print is our newest print-prepration software, which supports native CAD files and STL assemblies,
allows you to interact with all your printers via the Cloud, and many other exciting new features.
That looks like a fairly close match to what I ended up with after reworking my part. The very top can maybe be tapered to avoid the risk of a jam - together with a slight taper all the way up.. The root cause might be that the tolerances of the other parts all together puts just a little too much pressure all round, and i suspect the bottom fixing ends up rotating a little anti-clockwise. I wonder if this can be avoided by making the adjustment slots in the bottom support parts slope down slightly (so the adjustment range is increased by a couple of mm). With warping and rough edges, parts this size are tricky - especially if we didn't yet make 150mm calibration parts...
Thanks for the effort you're putting in to help us perfect our printers as well as your own!