It will definitely double or so , look at turbo's pics because, in another 6 weeks of his grow its going to be allot more thicker, not much taller tho , but it's not fighting for light.
Yes the weak lower colas at the bottom should go to give you more energy to the tops and plenty of air flow, which is important for this strain, personally I've never worried about humidity... I'd only worry if it was getting too hot and I was noticing leaf damage..but that has only ever happened once when I was pushing it to the limit, and backed off... A good thing having your low humidity tho is when they are filling out being in the 40% range for humidity would be ideal as you probably know b cause it is highly susceptible to bud rot...these buds grow dense like rock I check on them almost everyday praying to the weed gods they all good
)
Good choice in strain, definitely one of my favourites..
When they ripening reduce the light level and heat the best you can.. because it will easily burn trichs and cause foxtails...the second you are these signs, back off and let her do her thing.