I have changed my desires to get 8cm to get 5-6cm on femurs. I think being modest with a surgery like this is necessary.

Stretching nerves and whatnot sounds scary, so you have to really be conservative and give yourself two inches or a bit more (at least in my opinion) if you want to have a healthy recovery especially in old age. As far as I know, there's no one who's gotten LL 30 years ago [with the devices we have today], so we can't exactly monitor their progress now and see how they're doing in old age.

That's what I'll be doing. Would I want to get the full 8cms? Of course, but being modest is great. With 6cm I would be 176cm, which is about average height right on the dot. With boots on, I can bring myself up to about 180-181cm. That's good enough for me, I gotta acknowledge I will probably never be a "tall man" lol, but being an average height male beats being a short male.