Good that you've got a PAR meter. What light are you using and what are your light levels?
"I would have defoliated a little better maybe the main bud sites would have gotten more energy to grow bigger. because the plants that I see on this site have bigger buds . I was just wondering if defoliating makes a difference in the size of the colas"
I've seen nothing that demonstrates that removing healthy plant material from a cannabis plant increases the crop yield. Going back to basics, when healthy plant material is removed from a plant, the plant will attempt to regrow what's been cut off. I am at a loss to understand how that could possibly result in a larger yield.
Similarly, by removing plants to expose bud sites to light results in removing leaves that have been using light for photosynthesis and you are exposing parts of the plant that aren't used for photosynthesis to a reduced amount of light. In three (now 3 ½) years of reading as much as I can find on cannabis grow lighting and cannabis growing, I haven't come across anything that explains why bud sites would grow larger when exposed to light. I understand that it's part of cannabis grower lore but lacking any sort of substantiation nor understanding how removing canopy leaves could benefit the plant, I'm hard pressed to agree that it's a good idea.
Rather that remove leaves, I encourage growers to improve their crop in a very simple way — give your grow more light.
What's common across all evidence-based sources of information on cannabis growing is that crop yield increases as light levels increase. It's an almost linear relationship. On that basis, I've been growing cannabis at high light levels (>1kµmol when possible) and have a found that cannabis will generate prodigous yields.
In sum, give your plant as much light as it can tolerate, give your grow as few nutrients as are needed, grow it in favorable temperature and RH values (a VPD of 1.0 in veg and 1.2-1.5 in flower), remove as few leaves as are necessary for the health of the plant, and you'll end up easily exceeding the yield values that seed sellers publish.
Having said that, my practice is to remove damaged or heavily senesced leaves and, since my plants usually grow quite large (I grow one plant in a 2'2 x 4' with a res that holds 28 gallons of nutrient solution), I remove branches at the bottom of the plant that are thinner than a pencil. At that size, those branches will generally no flower of any appreciable size so, rather than futz with it at harvest time, I just get rid of them.
