Spillover WAN link load balancing
It should be interesting to have the option of load balancing spillover.
This option permit to use a link up to a configurable limit (MB or percentage), when this limit is reached the Sophos would start to use the secondary internet link too.
Johnny Khalife commented
WAN Spillover is a method where a threshold is set for an interface (in kbps) and if the amount of traffic bandwidth exceeds the threshold any traffic bandwidth beyond that threshold is sent out through another interface.