1st , look into this Layman-s-firewall-explanation , maybe you got in and local rules mixed up. (I always try to stay away from firewall_out rules)
Loadbalancing uses additional routing tables (201 and 202).
afaik the concept of multiple routing tables isn't present in cisco
The default route table is used for packets where LB isn't applied.
Just like Cisco, if your primary and backup WAN have equidistant default route , both routes will be used