Back again. Since I use a gasser, I guess I can answer your more direct question about when to add chips. For the most part, I usually add chips or chunks for about half the anticipated smoking time. If you figure 3 hours for applying heat to get the product done, I'd put the smoke to it for about 1 1/2 to at most 2 hours. The thermometers in the doors of the gassers are notorious for being off the mark from a little bit to a lot off. If you can remove the thermometer from the door, give it the hot water test. Boil up some water, to where you've got bubbles, stick the probe in the water and see what temperature you get. If you're at sea level, it should be close to 212*. Write down the difference, you'll need to know what that is. Then let the probe cool off and do the same trick with ice water, and see what it is. If you've got a meat thermometer (usually, a little more accurate) to compare it with, all the better. Plus, you have to remember, the door thermometer is only measuring the temp at the level where the probe is mounted. Higher up, the temp will be higher.
Chips. Better if you can get chunks or better yet, big chunks, but you gotta work with what you got available. If you have a decent chip tray made of cast iron, you're off to a good start. I usually just throw in a fair hand full of the flavor for the day (more an emotional decision than a scientific one), let that smoke )(gently, of course), then when its done generating smoke, I'll toss more in, on top of the old embers. Remember TBS. You gotta watch your temp like a hawk. It is preferable to keep the chamber temp in the 215 to 230 range (chicken or other poultry, with skin attached, I like to bump it up to 250-270 range). Top vent should be wide open. Bottom vents, on my GOSM (a big block smoker) I like to run fully open or no less than half open. As you become more familiar with the quirks of your smoker, you'll get more comfortable with what it can and can't do for you.
Since you've got some time before your dinner, I'd suggest running your smoker in some trial runs to get the feel of the beast. Yes, you do want to put hot water in the water pan. It will help stablilize the chamber temp and add some moisture to the cooking process. Remember, when adding meat to your smoker, expect a temp drop as the meat will be adding what we call a cold mass. Once the meat comes up to chamber temp (the chill of the meat disappears) your chamber temp will come back up. Don't be tempted to crank the gas flow up......if you have the smoker stablilized at your target temp before adding meat, it'll get back to it. If it hasn't within about 30 mins or so, I'll increase the glow, just a bit, but generally it's not a real problem. Got a remote thermometer? Don't stick the probe into the meat until the surface of the meat has been exposed to a minimum of 140* for a minimum of 30 minutes. Myself, if I know it's going to be a long smoke.....like 3-4 hours, I won't stick it until about 2.5 hours have passed. No point in any earlier, it'll just tell you your meat is still sorta cold and you've got a long ways to go yet anyway.
The real thing you want to take away from all this is that the foregoing is just the way I've been playing with my GOSM's (propane smoker) for the past few years and have had reasonable success with it. Other smokers will have their way of doing things and of course, that's perfectly acceptable.
Now, what you gonna smoke? We stand ready to help you through the whole procedure......it's our thing... you might say.
And, as was mentioned earlier, there are no dumb questions. If you don't know, it would be foolish to pass up the wealth of knowledge (or opinions, which there seem to be a lot of lately) here.
Remember TBS.
~Dave