You can start flowering as soon as they're rooted well. A lot of people on here do that, but I wouldn't. In my opinion that over ripens the Tricombes and changes the medicine's effects.
You're plants will double to triple in size when you flower, so it depends mostly on how much ceiling space you have and how much yeild you want.
I'm doing a 2 month veg because I'm setting up a rotating crop. See all my strains flower in 2 months, so as long as I keep the veg to 2 months, then I can have 8 plants vegging while 8 plants flower. Then when I harvest I have 8 more ready to flower, this way I have another harvest every 2 months.
So there are a lot of factors that determine when you're going to flower, so no one else can figure it out for you.