I got a most probable value of 1.55 C / doubling, a 17 % to 83 % range of 1.41 C to 3.27 C / doubling, and a 5 % to 95 % range of 1.18 C to 6.2 C / doubling... not far from your values (but I assumed a little higher total heat accumulation, including deep ocean uptake equal to 10 % of the 0 - 2000M value, and
some additonal heat for ice melt and land mass warming).