ORIGINAL: KFalcon
I think what he means when he says a 12 pound thrust turbine is a small model like a Yellow A-4 that weighs 12 pounds and is powered by a 12 pound turbine. One that has a high wing loading by design.
I agree with that sentiment completely. As with any model, whether it's a turbine or not, wing-loading is key to a plane that flies well.
In the case of going with a smaller motor over a larger, I would say get the extra thrust if fuel loads permit. The extra thrust can pull you out of some bad situations if used properly. In my opinion the 1/2 pound difference in weight between the larger and smaller turbines isn't enough to over ride the extra thrust.
The reality is that we're not talking about 1/2 pounds, we're talking whole pounds. Every little bit makes a difference to the way a model flies, and it doesn't take much thought before you can start shedding some really useful amounts of weight with some significant benefits - especially if you're just starting out. Like you just said, wing-loading is everything.
Phil