Selichot Timing

A timely question from alumna Gabrielle Hiller:

I have a question about the technicalities of Selichot: I see shuls have all different Selichot times, whether 10 PM, 12:45 AM, or before Shacharit. What's the support behind all these opinions and is there a preferred time?

Hi Gabrielle, it was so great to see you and so many of your classmates at the Yom Iyun - your grade continues to leave your mark on the school. 
The best time is at the very end of the night, right before dawn.  Also good is late at night, after חצות (close to 1 am - this is customary for the first night of selichot).  The problem with these, is that they are very hard; it means either going to sleep very late or waking up very early, which leaves you really tired the next day.  Therefore, many people are lenient and say it before their regular minyan in the morning, whenever that is.  Kabbalistically, the absolute worst time to say selichot is at night before chatzot.  Night is a time of harsh דין, and an inopportune time to plead our case for mercy.  Rav Moshe Feinstein allowed this if needed, but the 10:00 pm Selichot is certainly not ideal.

Gmar chatima tova.