Is there a hidur mitzvah to first place the wick into the menorah holder and then the oil after as it was done in the bais hamikdash? Is there a source for such a hidur in halacha? Also, why don’t we light 6 candles for 8 nights as the miracle happened?
I have never seen this hiddur, and I don’t know a source for it — although it is an interesting idea.
The enactment of the Chanukah menorah was not to light the same menorah as the Mikdash (with seven arms), but to light an eight-armed menorah in commemoration of the eight days.
Many commentaries discuss the inner significance of the eight arms of the Chanukah menorah (for instance, a popular theme is that the number eight indicates going beyond the regular order of nature, which is embodied by the number seven), though the simple significance is corresponding to the eight days, a different number of candles being lit each day to demonstrate which day of Chanukah it is.