As stated above, depends on your recipe?
Sea salt vs Kosher? Who cares?
Except that different grinds give you a different amount of NACL when measured by volume!
If you can measure by weight, I would recommend that, but many recipes do not come by weight?
I would follow your recipe and make adjustments after you have some experience?
Other than that, I have no preference between Sea and Kosher.
It is usually recommended to stay away from any Iodized salt for brining. Many, but not all, table salts are Iodized. And table salts will be VERY dense when measured by volume.
Good luck and good smoking.