Team,
Recently I participated to one of the Cisco partner briefing where they pitched iWAN design using internet as an alternate transport. With dual ISP connections, the increased SLA at reduced cost compare to MPLS. It leveraged DMVPN, WAAS, QoS, PfR features to achieve the goal. If I had a single router per site, its dead simple configuration but don't know how to implement with dual headend router. Would something like attached diagram be possible? How would WAAS function for such redundancy? I am not worried about other features but more worried about how WaaS and PfR would be configured.

Thanks in advance,