With little to no chance of burn from a small led seedling fixture, it will never saturate it in "too much" light as the output will not exceed optimal ppfd photon par flux density.
Depending on your grow space your main priority should be keeping the top canopy of the plant at 87 degrees Fahrenheit, doesn't matter how much light saturation you have if you don't have the photosynthesis production to deal with demand.
try keep ambient 84 lights on and use the led and get it as close as you can to make it 86 on top leaves, this will maximize growth given all other conditions are met.