318 Timing Chain Question.

I'm leaning toward leaving on TDC #1. then be careful to get it right with Dots on 12 and 12.
Use a straight edge to verify. It would have to be a tooth off to get it wrong.
I will have an issue that I'm doing it from high above looking down, and cannot get a front view. I guess I could use my iPhone and take a Picture to confirm/compare.
Opinions?