It will disable hardware offload on the WAN but local traffic should still have it enabled.
If you have symmetrical upload/download you can use 1 queue type, otherwise you'll need one for upload and one for download. You'll need to configure the bandwidth limits here. Change cake-bandwidth to about 90% of your max bandwidth. You'll also want to tweak it depending on if you're on Docsis, DSL, LTE, etc.
/queue type
add cake-bandwidth=250.0Mbps kind=cake name=cake-default
or
add cake-bandwidth=250.0Mbps kind=cake name=cake-download
add cake-bandwidth=25.0Mbps kind=cake name=cake-upload
Add the queues to the queue tree. Use the WAN's interface for the upload and the bridge for the download. I'm not sure if these bucket sizes are optimal.
/queue tree
add bucket-size=0.01 name=cake-upload packet-mark=no-mark parent=ether1 queue=cake-default
add bucket-size=0.01 name=cake-download packet-mark=no-mark parent=bridge1 queue=cake-default