I hear you, the water pan is good for long cooks to stabilize the temperature.
I'd rather have a
Stoker instead though:
I tend to agree with you that OO should be fine at 250F a few hours. For a long cook it will probably run off or convert before it goes rancid. I don't know about EVOO or VOO though. For the high temperature chicken that we were originally discussing cooking at 325F-350F, this is very close to the smoke point of EVOO (365F-400F depending on a few factors IIRC) so I might be concerned. Now, looking at all of this realistically, we're talking about less than a teaspoon of oil in a cooker filled with carcinogens from the smoke, so really, on that level it's irrelevant so long as it doesn't change the flavor for worse, which was my primary reason for abandoning it's use in this method of cooking.
I can think of a number of reasons people end up with dry chicken; a combination of both too high a cooking temp and leaving it on too long, it's a small piece of meat, the internal temperature can climb 10 degrees in just mere minutes, it seems fine one moment, give it another few minutes and it's too cooked, use of the highly inaccurate "juices run clear" test, and the fact that the USDA has revised their internal temperatures, it used to be 180F for chicken, now it's 165F. I have a pocket dial probe thermometer that is still printed on the sleeve with "Chicken 180F". I don't know if they are still being printed with those numbers, but if they are, and since they are available in every supermarket in the US, anyone who follows that number is going to have dried out food. Assuming that they even know how to use the thermometer properly.
As for beer can chicken, I can see how it could be considered extremely moist or even too moist depending on your tastes. What I love about it is the flavors that the meat absorbs when you've packed the beer cans with half a bulb of chopped garlic, four or five chopped habeneros, some chopped serrano peppers, and cilantro - now all these flavors are being infused into the bird during the cook.
I've also done cornish game hens on small V8 and tomato paste cans. This is nice for picnics and gatherings - everyone gets their own whole game hen.
As for lamb shoulder - no, never done one on the smoker. Done various cuts various ways on the grill, bit never on the smoker. No real reason, just never did. Something to put on my list for this summer.