I have always used water in the pan. Without it, or, something as a heat sink, it will be very difficult to control your temps. I have never had any problems with my bark because of the water, and have always used water because it does help with meat moisture. I also bought a larger water pan because of longer cooks, just so I dont have to "refill" it.
It has never caused me to burn "more fuel".
I also use the Minion Method for starting and start all three open full,and top damper full; then will shut one all the way, and the other two down to 1/4 open at 190 - 200. Once the built in thermometer zeros in at 225, I shut one to just barely open and the other I leave alone, but use that one for adjusting temp as the cook goes. Sometimes I will open it just a little more, but that seems to get the best air flow for any of my cooks. I can hold 225 top thermometer / 245 - 250 rack temp for a good 8 - 10 hrs. I do use the top damper for temp control, but usually only close it slightly if temp starts to spike. Have not had any taste issues by that.
Also, I use Weber charcoal, I find it burns longer, hotter, with very little ash residue and it does not have a "smell" to it.
Question, do you have the original door? sometimes you have to lightly bend it to get it to seal better, or you are getting too much air flow and constantly adjusting to compensate. I bought the Stainless Steel door from Virtual Weber site and it seals / fits perfectly, worth the money!!
Once you get a Guru, you wont have to adjust the vents (I dont have one, YET) or the damper on top.
That is pretty much how I run. Hope that helps.
Look forward to your future cooks!!