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.
There are two parts to retraction: distance, and speed.
65 mm/sec is faster than normal; 40 is the "stock" speed. One of the 3D printing gurus, "Chep", recommends slowing this down to 25 mm/sec.
The stock setting for Distance is 5 mm. He has 8mm. That seems like a lot to me, but to be honest, I haven't tried going that high, so maybe it helps with certain stringing situations.