To people who have lengthened 10cm

Is it obvious to the eye with all your other proportions? Small shoulder width for height ext.

You do know that taller people arent necessarily wider in shoulders? That's based on genetic factors-DNA, Race, Gender, and testosterone influence.
Theres plenty of tall people with small or short necks and heads as well.
From reading people diaries (the ones who actually got it done) not many notice at all. Most people dont realize that most dont fit the golden ratio in general. Very small percentage of people do.

Oh really? I might want to read a couple of diaries. I’ve heard it before but in think I’m just thinking about every problem before actually doing the surgery.

I understand but that is a sure way to spiral down and create even more body dysphoria. Most who comment on proportions are the ones most likely to get the surgery done on this forum. Also adding or decreasing muscles influences your body as well.
Read the stories with the most detail and the technology, doctors your interested in.
A lot of 'veterans' will dismay you on some things but remember they probably had a different method, doctor, and more importantly how fast they lengthening and did they abandon their PT intensity after distraction.
Those are keys to success. Everything else on the forum is probably more hindering than helpful.