When to flower???

This is my first grow and I am indecisive about when the plants should be placed in the flowering stage. They have been in the grow room now for eight weeks since I planted them in the large pots under CFL lights. The plants are of various heights and have all been topped and undergone low stress training. At this point I do not know if I should put them into flowering now or should I give it more time. I would like a good yield and am scared that if I put them into flowering now I will only have a small yield. On the other hand I understand that the plants still grow when placed in flowering which according to the strain will be around 63 days. I do however not know how much they will still grow during this time. Please can someone guide me. Do I go for flowering or do I wait and if so for how long? I have included photos of the plants as they are at present.

From what I can see it looks like there is still room to fill out the room. It may get harder to move around
when they get to flowering, but it will be worth it to let them get bigger.

Just a guess here... Maybe go to flowering in about 2 or 3 weeks. How much light are you planning to use
under flowering? What kind of light?

I will still be using the big CFL's but changing the globes to the warm white. At the moment I have 10 (105W) lights in the room and have color changing 50w LED. I keep this light on white at the moment but will be switching it to red when I go into flowering. The 10 lights have been put under reflective domes which I made myself (low budget). There is still quite a bit of space in the room but I need to move the plants away from each other as they are starting to crowd each other and the bottom leaves are not receiving any light. Thank you for your advice think I will give it another couple of weeks then and hope they don't grow so big that the grown room height is not enough.

General rule of thumb is they double in size during flower, height and width. I would flower now. With as small as those are for 8 weeks another two weeks isn't going to make a difference, just make them take longer to be done.

I have lifted the lights to the top of the room and they have gained significant height over the last 4 days. Due to this sudden change I am thinking that they remained so compact due to the fact that I have been keeping the lights very close to the plants?