As you gain more experience, and your WSM gets some 'seasoning', you will find the temps much easier to control.
Yesterday,I cooked a full slab o' pork ribs...a 7 hour cook at 230 - 240.
Started with some hickory chunks buried in a loosely packed ring of Stubbs briqs cold, and about 12 briqs started and on the top.
The point of this is that I use a clay saucer in the pan, NOT water, and was still able to control temps easily.
Your cooker will work fine with water, no water, or any other combination.
I was amazed to see this morning that about a third of the briqs aren't even ashed.