In my novel there are two main POV characters, third person limited for both. One lives in a tiny, cloistered universe without knowledge of the outside world, or the fact it exists at all. The other works at what can basically be described as a job in an international[intergalactic?] airport. They eventually meet halfway through. Who should I show first? Should I alternate? If I did that, the chapters of the character in the former scenario would be filled with dramatic irony. But I cannot leave out the events that lead up to the latter character meeting him. Should I accept it and move on, or choose one over the other? Sorry if I'm being too general, please let me know if I need to clarify anything.
I would come up with which scenes are important and in which order they should appear. Then, from that, figure out which POV character best fits the scene.
Basically, this. ^ You have the very basic story line you've mentioned above (and I'm sure more detailed than you've told us). I would start with your fictional timeline - a basic outline of the major events in chronological order. Then I'd think about what I want the ending to look like, what it means for both characters. Each character will have an emotional response that you want to register with the reader, but one may be more important to you, the writer, than the other. Know that up front, because it will make all your other decisions that much easier. Finally, I'd work backward from that ending to determine the order in which I want to tell different elements of the story. In all likelihood, the POV you want to start with will be the character whose emotional response at the end is more important to you. One final comment: when you finally have this planned out, remember that it is a guide, not a straitjacket. Be open to new ideas that occur to you as you develop both your story and your characters. Good luck.
Thanks for the timeline suggestion from both of you, it really helps! Even though I've written for a while, I still have issues balancing planning verses winging it. Finding that right balance is challenging. I know how I want it to end and how both characters react to and feel about it, but that came easily to me since they interact from midpoint of the story onward. It's the introduction and revelations of hidden knowledge that occur earlier in the story that give me trouble.