A buddy has asked me to build a couple of On30 switches for him, for his small switching layout that is 2ft by 6ft. What I need to know is the size of the switch ties ? Do you go normal switch tie measurements with an O scale ruler? Can you use HO switch ties (properly spaced) ? He has a 0-6-0, I am assuming the engine and cars will navagate a #4 with minimal difficulty or should I build #6's ? Thanks Ron..