When do lights go 100% intensity?

Well, this fully depends on the light and the environment.. The best method would be to actually test the light intensity (PPFD) at the canopy (so what really hits the plant). To get them to flower you'd need at least around 400um/s.. Above 850um/s you'd want to add some extra CO2, so the plant can handle the light intensity properly. Looking at the light you have, that seems to be able to push out 1620 umol/s, so you depending on your environment you might not even want to turn it up all the way, as too much light can actually harm the plant as well.. Do you know the light-color of your LED? No need to buy an expensive apogee quantum meter, but Shane from Migro made a review video about a cheap 30-bucks Amazon par-meter and made a test, comparing it to his Apogee, and then provided a conversion factor for the various light-colors, so you can calculate the LUX to PPFD and save about 470 bucks (compared to the Apogee) ;)