I agree with what's been said, just load up with lump with about 4 wood chunks and let it slowly get to temp. No need to reload every few hours, unless you are practicing for your future stick burner!
IMO a water pan in a kamado cooker is not a good idea. You bark will have a hard time setting. By setting I mean it won't be soggy and easily smear off. There are steam burns too you have to be careful with. As far as when the brisket is done, when it probes tender in the middle with a wooden skewer or similar it's done. Let it vent to lose excess heat for about 10 minutes, then stick it in a cooler to rest. I like a long rest period (3-4 hours) when possible. Otherwise let it rest out in the open for a little while before you slice it.