I tried myself at this and I'm stuck.
I have counted five candles all in the "succubus spawn" area, and a candle on the third shelf.
So I tried :
12 hours
5~ minute (brute forcing kt)
22 seconds
I then switched hours and minutes; I'm stuck, help please.
Then I tried the same method but with 3~ because a candlr is on the third shelf (in the same room, just below where there's a note)... nothing.