It sounds like you have a single area to work with, rather than seperate Vg and Bud areas. Plants should be at least 12" high, and if you can force branching that will increase the number of buds. I'm not sure how much a small (proto)branch will grow after budding begins in earnest.
Males express first, within the first 2 weeks of 12/12 (sometimes as quickly as 2 days). The "balls" appear first at the nodes and quickly show up on the branches. A few days after that they're very noticable.
Females start growing buds during week 3.