Cisco OER Implementation

I am in the process of designing an Intercity link between our two main data centers. Due to some mission critical applications, we cannot afford to sustain an outage for more than 90 seconds.

Currently we have two links, 1 Gig and 600 Mb, connecting the two data centers and we are seriously looking at using Cisco OER to provide automatic failover between the two links.

My understanding of OER is the convergence after a link failure, prefix falling out of policy, could be 1-2 minutes. Is my understanding correct, and if so is there anyway to effectively shorten the convergence time?

Thanks in advance.