Sourdough with thick, tough crust

Toast

What are the factors that will contribute to a thick, crusty crust on sourdough?  And what will contribute to a thinner but still crunchy crust? 

RB

I wonder if minimizing the time under the pot to, say 5-10 minutes, might give a thinner crust?

I didn't use a pot or cloche, but I did give plenty of steam for the first eight minutes only.

RB