How long does a dyed lacrosse head take to get full color (black)?????

You definitley want to take the head out now. It really doesn't matter how long you dye it for as long as it is around 30 minutes. The whole idea of dyeing the head is that the plastic in the head has empty molecules in it and when you dye the head they get filled with color which gives the head it's color. The empty molecules are pretty much like a bottle once you have them filled with dye you can't put any more in, dyeing it for a longer time really doesn't do anything. The problem I see most often with dyeing heads black is that they turn out a purpleish color and you might have to redye it a few times to get it solid black. And yes to get the paintsplatter effect you want to dye the secondary color first, hot glue the apropriate places, and then dye the base color second.