First of all, 8cm on tibias is a huge amount.
Second, that man had already relatively long tibias compared to his femurs. I did almost the same amount (7.5 cm) but my tibias don't look that long because they were very short before LL.
Third, that photo is maybe a little after removal surgery. If he workout his legs he would look better. Not perfect but still perfect.
It would be better to stick to about 6cm, especially since he wasn't short to begin with, but still he does not look bad. Just not so normal. But he looks really tall (much more than 1.81) and with some work out and clothes on he will definitely look better.
And even without clothes, almost noone will see an alien, just a man with very long legs.
People are not like us here to care so much about proportions. I've seen much worse proportions to men that are models and women do like crazy about them.