This is how your bonded broadband setup should look if you are using two Power Router with a switch, using routed IPs.
In the sharedband config, of both routers, the VRRP Gateway should be set to the Gateway IP address from your IP subnet. This is normally the second to last IP address from your block. The Virtual Router Netmask should also correspond to your subnet and match on both routers.
The subnet you require is specific to the number of IP addresses in your block:
|Number of IPs||Subnet Mask||Slash Notation|