So in a lab setting, how much of the "Warming" is attributable to a 120PPM increase in CO2
So vague as to be meaningless. You'll need to describe this "lab setting", exactly defining every piece of equipment and environmental variable.
I suggest you look at the HITRAN database to get some answers. HITRAN is maintained by those well-known pinkos at the Air Force to precisely catalog the spectral absorption of all gases found in the atmosphere. They are constantly updating and refining those measurements. Dig into a bit, and you can find the papers describing the lab setups to get the numbers. If anyone wants more than that, go get it yourselves, ya big lazy lugs.
HITRAN
Now, if you'd like to tell the Air Force that they're doing it all wrong, and that CO2 really doesn't absorb infrared, I'm sure they'd love to hear from you. Give it a shot.
The history of the science is interesting. The first experimenters screwed it up. They send infrared radiation into a tube, and found adding more CO2 didn't change anything, because the CO2 absorption band was already saturated over that short distance, and thus they concluded CO2 wasn't important. Deniers here usually make the same screwup. They miss the fact that when CO2 absorbs heat, it re-radiates more IR in all directions, meaning each little layer of the atmosphere keeps absorbing and re-remitting. A tube can't simulate that 3-dimensional situation, being the tube is close to approximating a 1-dimensional setup. It wasn't until the 1950's and the first computers that scientists correctly figured out what was going on with CO2 in the atmosphere.