Hello, just installed my set of ball cup arms.
I am very pleased with them, they seem quite abit tighter and more secure than the stock arm arrangement.
Also I have the e3d v6 hotend, I used this mount with no apparent problems, http://www.thingiverse.com/thing:1064131" onclick="window.open(this.href);return false;,
the nozzle doesn't protrude below the arms as much as it did with the original effector plate, but no problems yet.
General info from SeeMeCNC HQ