Yep, the bigger the light, the fatter the colas. For really big plants, veg under the same light intensity that you flower under. For example, if you are using a 1000 watt HPS, then veg under it too. The more veg time, the more bud too. Also, proper pruning comes into play as well, All of your plant's energy focus should be on maybe four branches, maybe six. Everything else (lower branches) should be trimmed away starting with the flip to 12/12. That's the time to take cuttings too. If you're growing SOG ... then all the energy focus should be on the one main cola.
Vi