If a strain gets up to about 5ft, and you LST it, on average what would the plant height be once it finishes flowering and is ready to harvest? 3ft?

Iam a noob, I dont have that much space in diameter or height, so I can only do about 2 plants at a time. So I want to maximize my yield by tackling big yield strains through the LST method. Once I know the limitations of LST on plant height it will help me make a better choice for my strain.

Depending on the strain and if she was a reacher a big tall girl, i would maby top her ( im not a fan of topping) in veg 1-2 weeks before flowering, to even out the side branches, to creat an even flow of the plant, which will also reduces some height, , but if you didnt want to loose the main cola.... which most dont, ( i dont)

Tieing her down will also create the same affect as above but without loseing the main cola, i do my plants in a ( S ) shape , and by doing this i dropped her height as much as a foot maby even two, and it allowes the sides to move up, ( but you may find your self then tieing down the sides as well, i can be a pain) but i have found the work and effort brings some real great colas,and nice yields..... ( Its not rare for me to have 6-8 cola's all as think and juicy as the main)

Most important, is to start this early, in veg, this way when in first weeks of flower during its strech your still in control of the tie, you should be able to keep her short but it will become bushy...

Look her or them over good, see which way looks best for them and do the ( S ) tie-down

My thoughts any ways.....

Wow, Mercy38 hit the nail on the head. There's nothing to it but to do it. Remember your plant will at least double in size during flower. Just make sure you leave enough space. Look in to Super Cropping, works great.

hmm double in size during flowering?
Yeah so, lets say you LST a plant and its about12inches in plant height after veg, when it finishes flowering it should be about 30 inches in plant height?

Again this will also very on your lighting, if theres not enough, light she will reach for it, it will all depend, on the strain, lighting and enviroment and the effort you put on her, but its very probable you can achieve your height goals...