12/12 vs 16/8

How much less MJ will I be able to harvest if I use a 12/12 light cycle as opposed to vegging at 16/8 and then going to 12/12. Assuming the strain, watering, nutes, etc... are all the same for both light cycles. Does anyone have any experience with this? Is it worth the effort to get a quicker harvest or let the plants veg longer?

12/12 is the proven way, if there were other light cycles to use to yield more you would of heard about them. Just veg them long then go 12/12

Plants store energy from the sun during the day and make use of the stored energy at night. The perfect number of daylight hours depends on the light strength. With a strong light source, the plants can spend the entire 12hrs of darkness using the energy they collected during the day. If you increase the light hours with the same strong light source, the plants may not have enough time to use up the energy they stored, causing light poisoning. People have different opinions on ideal photoperiods because people use different lights.