Light saturation point? I would be interested to see a journal article or two about this phenom. That term is typically used to describe the maximum intensity that a plant can utilize to produce carbohydrates through ATP and it is NOT time based. Time has absolutely positively NOTHING to do with light saturation levels yet, as is somewhat typical for you, you understand most of the concept then staunchly apply it in a wrong way. Saturation levels for MJ are around 90k lux. Above that tissue damage may occur. I don't know the exact light saturation point but it's safe to assume it is reached as this lux level is higher than what is typically experieneced under natural light.
The major point here is that discussions of time and light saturation are not appropriate as they are completely independent of each other. Plants may UTILIZE sunlight at different rates dependant on time, but the limit is completely static.
MJ is a C3 plant and fixes co2 through ATP and NADPH molecules. It's not a staggered cycle of absorption and then fixation during the dark like C4 plants. As long as the light are on, the plant is "working" and growing. As stated before, the ciracdian rhythm still applies and a plant will slow down its rate of CO2 absorption as the light duration is extended past what is typical but it will adjust to 24 hours of light.
Obviously the temperature has an effect on growth rates, it an endothermic (takes heat) reaction. Plants are like lizards in that respect. As long as you increase the availability or intensity of other limiting factors (co2, light intensity, nutrient availabilty), growth rates are directly tied to temperature.
This is newb stuff guys.