Hardware size for mounting large rear basket?

[MatthewK]

Hello,
Just took shipment of my RadCity 5 plus and was in the process of moving my large Rad basket FROM my Radrunner To the rear rack of new bike and that's when I discovered the hardware is not compatible. The Radrunner used a larger diameter and longer bolt that you attached a nut to the bottom. The Radcity is smaller diameter and length and just threads in. Anyone know the dimensions so I could pick up at hardware store versus trying to order from Rad? Thanks

Matthew