Does the phrase quintessence of perfection make sense?

Sure. We might say, of a fallen hero for example, "Remember him as he used to be, not as he is now." Or, with another meaning: "I thought he would know about the trees, as he used to be a forester."

In the UK the phrase was used in government sponsored television commercials promoting the use of car seat belts before this was made compulsory.

Yes, 'you can' does make sense; you're simply saying 'able to [do something]'. A person might say, 'You can visit the library,'.

first of all we know about what is sense? sense mean you work on a topic or think on his work.sometime we live a easy or simple life because our sense work those.