So I have used both before for separate projects outside of growing. It's been years since I did a grow. Then I used a 400W HPS in a closet. Now I am in two small chambers. 2ft x 1.5ft x 3ft high. I have a veg chamber and a flower chamber. I am concerned about space and heat. I can save space by using SIX 23w bulbs saving maybe a couple of inches. But will SIX 23w bulbs create more heat than two 65W bulbs? Lumen difference is between 50-100, and wattage is within 10w of each other. Debating on which to go with. As I am having to place an order for either. Simply don't have a good 6500K veg bulb in my area! And it's cheaper to order from a bulb company than any of the hydro places. Any help is appreciated!!