short torso how much should i lengthen my legs?

Edit Post

I'm 171 cm, I want at least 5'9 -5'10 (175-178) but what worries me is my already long legs and small/short torso making my overall stature disproportional.
My inseam is 80 cm, my height at night is 171 cm, the ratio is slightly above average? 46.8%. When I look in the mirror, my body doesn't really match my legs. Could lifting to increase my torso size helps to make it more proportional? And what is the safe point for the length of lengthening?

Edit Post

my sitting height is around 81-83 cm

Edit Post

error, it's either 83 or 84 cm

Edit Post

my arms are long, tip of middle finger goes to half of thigh.

Edit Post

I remeasured my sitting height and it' actually either 86 cm or above. It's abit hard to measure it accurately, but the first measure was on a puffy curvy chair, now that i've remeasured it on a wooden chair, the result seems reasonable, 86 cm or so.

Edit Post

with this, I think I will try 5'10 max if not, 5'9.