I don't have any experience with the Leila however I would think you should be able to get big clouds out of it if you put enough heat to the bowl. I have a Mya Petite which is a very tiny rig and can get big smoke out of it. Big clouds have more to do with the tobacco and the amount of heat. I might be concerned with putting too much coal inside that thing. I think I read some of the reviews on hookah-shisha.com that said the unit itself couldn't handle a lot of heat. Here's one..
When I first got my Leila, it was perfect. Great smoke and cool design, the LED sets it off for the night just right. Unfortunately, the heat from the coal melts the adhesive on the heat sheild! The plastic beneath it will seperate from the metal and becomes useless. Thats not even the worst part, give your hookah some time ( mine about 2 months smoking every two to three days ) and the plastic seal that holds the hose to the pipe will break. The heat, smoke, and water will swell and loosen the seal, totally destroying the pipe. Since the seal cannot be refit after it has been damaged. A $1oo.00 pipe, now it's just a night light.