2000 Pontiac SSEi, supercharger belt, pulley(s)

Front idler pulley for the supercharger bearing locked up and, and the plastic pulley disentegrated--belt was lost. Replacement pulley is a steel cup rather than plastic. It was siupplied with a hex head RH thread bolt rather than the original TORX head LH bolt, but this was easily replaced with the original LH bolt. I suspect that the replacement pulley is a larger diameter than the original because the only replacement belt listed is too short. It is not short by much, but with the spring loaded idler rotated fully ccw, there is not enough slack to install the belt. Is an original smaller diameter pulley available, or is there a different (longer) belt that you can recommend?
I feel certain that I have the belt routed correctly, but just in case that I am wrong, do you have a pic of the routing?