This is the topology which I have used for the following tests.

I have found out that the convergence time of the routers in the above  topology can be calculated from the number of pings lost multiplied by 2 which is the specified  timeout. In the first output we lost 8pings x 2 =16seconds. I verified this also from the wireshark output which gave me  15.8840seconds. It took about 16seconds after shutting down R2’s serial interface S1/2 for the routers to notice that and begin to use an alternate route to R1’s loopback network 1.1.1.1 via R3. (R5àR4àR3àR2àR1)

Bandwidth

I have noted that bandwidth would not affect path selection until the available bandwidth on the preferred route falls below 885kps. If it does not fall below that the preferred route would remain in use regardless of the huge differences say 7500kbps vs 885kbps.

From the above outputs does not show any significant differences on the speed of convergence at the moment. It needs to be tested with traffic flowing in the network to figure out if the results will be different.

Sorry I have had difficulties in posting all my test result I will put them on google docs.