Looks like you're going to have an amazing harvest. I'm lousy as guessing harvest times, but it's a ways off. Best I can say is ask again in 2 weeks. You'll be close enough for someone else to judge by then.
Keep the string on that plant or stem will shoot back up.
Humidity should be between 40% and 60%. Some growers worry about mold and keep it at 40%, but mostly I hear 60% is ideal for flower. 50% is good, your plants look great, I wouldn't change anything.