[B.A.T.M.A.N.] MTU for batman-adv w/ vlans?

I'm not 100% clear on how batman-adv works with vlans, so excuse me if I've taken a wrong path.

I have a small 2 radio mesh node with 1 ethernet port for non-mesh access. wlan0 and wlan1 in bat0, bat0 and eth0 in mesh-bridge.

MTU is 1532 on WLAN0.

If I want a VLAN to pass through the eth0 interface as if it were trunk, what needs to be done? my thought was, increase WLAN0 MTU to 1536 and eth0 to 1504....

will that work? or do I need to create a vlan bat0.1 and eth0.1 and bridge them?

Thanks