What you're talking about is usually reserved to mean load balancing over multiple NICs on one network, when your NICs don't have large enough bandwidth to handle all of the traffic on just one. This, unfortunately, won't help in this situation because all of his traffic is not on one LAN. He's trying to distribute his traffic across two default routes, and that's much more difficult to do well, since, in order to get it to work well, you'd have to coordinate with the upstream providers and get them to coordinate amongst each other. Which is not going to happen in this case.