Ah the great debate: To record your voice in MONO? Or in Stereo?
Some audio types INSIST that in order to get the best clarity and such from your audio, you must always record in STEREO.
To this, I say POPPYCOCK!
Stereo voice tracks, in my estimation, accomplish one thing, and one thing ONLY: They chew up your hard-drive/storage-space TWICE as fast. I would be inclined to suggest that a MONO voice track will give you more "presence," but I'm not entirely sure that's more than opinionated nonsense, to be honest.
IF however, you're going to try to do some cool little tricks with your audio, say, to match your video...let's say for example that "Karen" is on the left side of the screen, and "Ralph" is on the right, you might want to mix the track so the character audio is dominant to one "side" or the other. If this is the case, it's easy enough to convert a MONO track into STEREO, and play with the "Pan Volumes" from there. You can actually create some nice effects. However, you don't want to put ALL of your audio to one side or the other...it really gets weak and sounds "far away" or "low volume" if you do that. Rather, mix it so that it's....oh...probably 65% dominant in the proper channel, and 35% in the weaker one...here's an example of such an approach:
Stereo-Split Demo Track
If you listened with headphones, you'll notice a definite difference in the "sides of your brain" voices versus that of the "announcer" voice. But while the two "sides of the brain" were mixed in Stereo, the two voices weren't EXCLUSIVELY assigned to one side or the other. It may sound like it, but trust me--you'd know the difference.
For voice...as a narrator who makes his bread and butter (as it were) from this very thing, MONO is the way to go. You can do a great many things in post-production if you have the inclination. In fact, the sky's the limit. If you need pointers, regardless of software, let me know...I'll be happy to share my experience with you.
Best of luck!