I bought an older Kinze 2600 this Winter, 16/31 w/no till coulters. It worked great in no till and conventional tilled fields. It is kind of a pain with 31 boxes trying to split a 50 unit box of seed but I'm satisfied. I wanted to keep my other planter for corn so I couldn't justify central fill for my bean acres. I'm not sure if the narrow rows yield enough extra to justify the cost of  a narrow row setup but I don't like all the exposed soil between wide rows after harvest so I partly do it for erosion control.