Heyyy! Wow I have a thread... like... asking for me! Not HARDDON or Zandor... me boo yeah! Anyway! I'll asnwer the questions as best as I can:

1.) I topped them at 18 days (from germination to now, 21 days).
2.) All I did was cut off the main stem. At the top of the plant you will notice two steams break off (into a node) and rising out of the node is two more baby leaves ready to spread out. What I did was I went between the leaves and cut the very top of the main stem right off. so basicly, I took the top off my plant. I used steril scisors.
3.) They were on their 4th node up (4th set of branches). The plant was only a few centimeters taller than an average sized lighter, maybe 5 or 6 inches.

To get results like mine, make sure you have LOTS of light really close (if you are using compact fluro lights) and make sure a fan is on the plants at all times. What are your growing conditions? Gimme some info, and I will help you out as much as possible! The more light, the tighter the nodes are together. Once you top the plant, keep it in veg and allow some time for the lower branches to grow out and new branches to begin growing. Best of luck! Get back to me on the info...