Flowering Questions?

I have a few questions about the flowering stage here. I am looking to put my plant into flowering soon and was wondering how much more does the plant grow up when in flowering and what is a good height to put the plant into flowering? If i was to put it into flowering when it was 1 foot hight would it be 2 or 3 foot at the end? I am running a stealth grow of some northern lights so i have limited room. It is currently about 17cm high at the moment.

Any answers would be great!

plants could easily double in size what i found that works good is when flipping to flower lowering your lights as to stop the stretch phase at the begining of flowering

You can count on it double to tripling in size at least.

would that reduce the amount of bud i get?