they are kinda small but practice makes perfect I would say for 4 weeks in those are about average size not as big as they could be but like I said practice makes perfect. expression of gender on the other hand is strain dependent and can take much longer before it occurs. with the proper conditions you could see sex in 4 weeks but that is not that common. easiest way to determine sex the soonest is to take a clone and put it on 12/12, they are big enough to take a clone should you choose and you can put these clones under cfl on 12/12 to determine sex.