Smart Queue - limit LAN bandwidth?

I have just finished migration from an ER-5-POE in my tower cabinet to an ER-PRO in the main comms room, and have a doubt about the Smart Queue feature.

I have an underground ToughCable running to a guest house, and I would like to limit how much bandwidth they can draw.

I was thinking of doing the following, for eth1 which I would connect the cable into:

set interfaces ethernet eth1 address dhcp
set traffic-control smart-queue "Caseiro"
set traffic-control smart-queue "Caseiro" wan-interface eth1
set traffic-control smart-queue "Caseiro" download rate 0.5
set traffic-control smart-queue "Caseiro" upload rate 0.5
commit
save

Is this the right way to do it, and does it work well?