EZ-Mate Mark II Couplers for Atlas Ore Cars

[jbodensteiner]

Hi All,

Very new to model railroading, particularly in N scale. I have a number of Atlas ore cars (+20), and I would like to convert the old "horn" style couplers on most of them to EZ Mate Mark II (which are already on some of the engines I use). There are three shank lengths available. Can anyone help me with selecting which shank length to order? Twenty of the wrong ones will be pricey. Thanks.

Joe