A couple weeks ago, late on Friday afternoon my employer handed me a Platinum mounting and @3ct Diamond, saying he had just sold a $40K Diamond, which I could set on Monday morning.
Before I left work on Friday I handed him the job, done, and he said: "But I told you it was OK to wait till Monday!"
Like I wanted to spend an entire weekend knowing that first thing Monday I would be setting a $40K Diamond. Just sit down and do it. The more time you have to worry, the more you fixate on risks of a project, the more likely you are to have an issue.