Looks like you're making do with what you have, very ninja like. Lamb is so expensive here (sometime 10-15 $ lbs). Coals are off too one side, nice. Try using a basket to help control burn if you do longer cooks. If you seal her up enough with a lid gasket you should be able to use fuse/minion method. Others know more than me. Enjoy.
"the only goal is success,the path does not matter" this is my nindo.