If it's straight veg I'd go with the 5000K. 6500 is daylight and 4000 would probably be if you're only getting one light for veg and flower. More light/lower wattage is always a good thing .
If you really want to know how much light is happening, get a umol meter. They're all the rage now for folks gauging the amount of light their plants are receiving.
If you really want to know how much light is happening, get a umol meter. They're all the rage now for folks gauging the amount of light their plants are receiving.