HPE 2920-24G switches to Watchguard multi wan - Dedicate Voice vlan to secondary External

Setup:

3 HP 2920-24G switches

2 Vlans - Voice and Data

Windows DHCP Server - hands out addresses to 10.x (Data) and 150.X (Voice)

I have the IP phones working as expected and hopping on the voice vlan, getting a new IP from the voice scope and working as expected. The only problem, is our main connection has a high latency route to the PBX location. Our copper connection (Secondary external) has a low latency route and I want to specifically force the voice vlan to use the secondary external to help with the delay problems being reported by users.

I've tried using policy based routing (override checkbox) and created both vlans within the watchguard. When I do this, the phones drop their IPs and no longer get an IP address at all. I've tried setting Send and receive tagged traffic for selected vlans on both vlans and vice versa in case I had everything backwards. I also tried setting send and receive untagged traffic for the data vlan. Data flows as it should, but the voice vlan just drops out. I know this has to be something simple I'm missing as I'm not much of a network admin, more sys admin than anything.

Watchguard info: Int type - VLAN

Vlan1 - data ipv4 address is the address of the watchguard

vlan10 - voice ipv4 address is the address of the switch with the route to the 10.x network

I've setup policies specifically for all mitel ip phone ports

From Any-external To Vlan10

From Vlan10 to Any-External

Both policies have PBR enabled for the T1 interfaces.

Thanks in advance!