Do you agree that the no-feedback response from 2xCO2 is roughly 1 K?

Roughly 1-1.2K.

I think that's pretty accurate based on these assumptions:

1) The quartic-root-mean-to-the-power-fourth temperature is close to the mean temperature (which would be the case if the probability distribution function of temperature at a random point on Earth is symmetric about its peak)

2) There is relatively little increase in conduction through lower layers.

3) ModTRAN outputs and satellite measurements are right about doubling of CO2 being a ~3.7 W m^-2 increase in downgoing longwave radiation.

From my thinking so far, I'm not aware of anyone showing that these are wrong.

Many attempt to argue against 3), but they're mostly based on sheer ignorance.

Yes. I don't claim to understand why but I accept it as roughly correct. This is the figure most often quoted here, not just by proponents, I've seen this from skeptics too.

Having said that, 'skeptics' come up with many values; 0.5K seems to be gaining popularity, 'tiny' and 'zero' are often seen too.

There seems to be a rough correlation between the value quoted and the probability of their argument having any merit!

For example, one 'top contributor' who claims 'zero' for 2xCO2 puts the warming down to the solar system crossing the galactic equatorial plane!

I'd agree with roughly 1K although I’d be inclined to go with 1.2K.

We need to define a starting point. Tending from 0 gives more consistent values and a reasonable starting point (chronologically and numerically) would be the pre industrialisation figure of 280ppmv (1750). From this start and excepting feedbacks then 1.2K works.

that is stupid to anticipate that the aspects isn't gentle to fluctuations. Deniers want to point out that climate has replaced interior the previous is ultimately information that guy won't be in a position to be effecting it. on the different, it basically exhibits that the aspects is extremely gentle to small fluctuations. humorous how Portland Joe's answer seems merely like various of NW Jack's solutions....hmmmm

Yes.