Draft Tech: How many copies should I play

I was listening to LR episode 205 and they were discussing how many copies of Sip of Hemlock to run.

Thinking more broadly I would like to discuss playing multiples of a card in limited. Often we draft a bunch of the same card but it's not right to run them all. Certainly curve considerations can be a deciding factor. In the case of black removal spells. I would speculate that I would need quite a few doom blades before I would consider cutting one but the Theros staple, Sip of Hemlock, not so much.

 

        i don't know 5 of them                  probably not more than 2

How about something where your curve can easily handle as many as you could reasonable draft. Say

I feel like a deck could handle 8 of these no problem. I don't really know where I'm going with this post. This is just a question I've been rolling around in my mind for a few years. Drop me some thoughts in the comments. And a question for the audience.

How many Celestial Archon would you run? How about Spear of Heliod?