Coil Binders — Punching for Plastic Coil

Some coil binders can only use this new .2475˝ pitch with all books. Some can use a 3:1 pitch, but that will look unattractive on thin books. Some coil binders can use any pitch. It is recommended that you move to a bigger pitch when binding books thicker than 22mm in diameter. Popular sizes are: 3:1, .312˝ and 2.5:1. What are the reasons?