What is your sitting height and wing span?
2 surgeries for 8cm is just not worth the time, effort, and money and other opportunity costs.
do a mock up of 8cm in Femur alone and another mockup of 8cm both in femur (16cm).
don't worry too much about how you look in your underwear, only a handful of people will ever see u in your underwear.99.999999 of the people in your life will only see you clothes, unless surfing is a big part of your life.
171 is better than 163. But why stop there when you can get to 175-180cm. at age 35yrs athletic ability is of little value in your life.
just my 2 cents