JimD, it only takes the oceans about 8 to 10 years to catch up based on a variety of estimates. That is of course the bulk mixing layer, not the total oceans.
As far as CO2 expanding the tropics, it basically just expands the moist air surface area, tropics, subtropics what ever, you can compare models with regional temperature to see how well they got that right.
I know you are counting on the oceans coming to rescue your higher sensitivity dream estimates, but reality is going to be a beyatch.
The difference between your estimate and mine will boil down to who has the most realistic assumptions.