Nice plant!
To try and answer your questions:
1. When should I take it to the plant or flower cycle?
- considering the plant can grow twice it's current height during flowering stage, and your canopy is pretty much flat, you can flip her to bloom now.
2. Can I use Biobizz Grow and Heaven in the flower cycle?
- according to BioBizz's feeding recommendations, yes. Both will eventually be increased as the weeks pass and if your plant desires them.
3. Do you have any suggestions for light distance and dimmer settings in the flower cycle??
- every light and every plant are different, as is every grower. Dunno what height and intensity you are at currently but when I flip to flower, my light is at 50cm @60% intensity. By the time the plant is ready to harvest, the intensity has been slowly increased up to 80%. Anything more than that and my plants react.
Some growers hang their lamp higher, say 75cm away from the plant at 100% intensity. With a lot of lights, that evens out the par on the canopy level at such a distance.
Hope that helps a little. And have fun growing!
like