Hey Galo, So I was reading your journal and based on what your doing, the amount of room you have to work with, I would take that stem and bend her over and tie her down to the edge of your cup. As she grows, keep her tied down to the edge of the cup, when you get all the way around, take her out of the cup, cut 1cm of her root base off all the way around and the bottom, replant back in the pot with new dirt then bloom her.
I was going to suggest you top at the first node and bend the 2 tops sideways forcing side growth to become apically dominant. As wood material breaks down it leeches nitrogen. you may see some early yellowing because of this....
Should I top and bend it now? I was going to top and scrog/lst, but everything I read said to wait until the 3rd or 4th set of leaves.
Gives your root structre room to grow during thr first 2 weeks of bloom and not have to move to a bigger pot. I do this with my bonsai mums every 8 months or so.
In terms of size look up some plant training methods such as LST, SCROG, And topping/fimming. You will have to use those in your grow or else it will get too big for the box and start touching the lights which is bad!! Out of all those i reccommend LST the most for your size restrictions. Also with a micro grow it is best to start with the pot you plan to keep it in its whole life. Idk if that is your plan with the cup but you may want something a little bigger so that you can actually do those techniques properly. Edit: I just noticed that you know about these things lol. I should read more before posting things sometimes.
I have a much bigger pot that I was planning to use, but now I dont know, I think it may be too big. Here is the party cup inside the pot:
A pot like that is actually perfect for pc boxes, now Idk the dimensions of that particular one but if it fits in the box it is perfect for LST in the small size available. Plus more soil = more roots = more buds so you can't loose as long as you train her down properly. I will search around for this one thread where that type of pot was used in a pc box with amazing results.
Found that thread I was talking about. Just do everything this guy did if you can, he ended up with a huge yield from a pc grow with a rectangle box and LST http://forum.grasscity.com/micro-grows/958449-mrbear2point8s-pc-bagseed-grow.html
looks like you have a little sativa there..... not sure itll be ready by the time you leave your country headin this way..... you might think of when you'll switch to 12/12..... most sativas take around 10-14 weeks of FLOWERING.... that dont count the veg time.