I’m currently using a MiFi to as an ad-hoc Dual-WAN router that load balances between a wired ISP connection and a cell-based data service; this setup should be equally applicable with any of your mobile routers with an attached dongle. I would ideally like to have active VPN connections on both, yet have the benefit of load balancing (i.e. have the VPN client between the load balancer and the network interface).
When I use the native OVPN client, does it automatically create a separate VPN connection with both interfaces? If it doesn’t, how does it decide which interface to open a VPN tunnel to?