In landscapes, I never use secondary lights as ambient light. Instead, I use the "sky dome lighting gain". I find the result much more realistic and natural than that of a secondary sun. Only my opinion. :-)  It renders faster too.

Quote - "when i look at clouds and skys there are so many factors that i feel overwhelmed. do i start with experimenting with different light models? do i start with cloud attributes? how does camera and sun stuff factor in? this kind of clarification is what i was hoping for."

I don't think there's a start. Every one of these things contribute for an atmosphere. You have to use it all in parallel. This is why I said that experience is the key thing. With experience, you immediatelly know what you have to change to get the look you want.

Each person has different opinions on all of these things, I think. For example, I only use GR lighting model (only in one or two images I used GI), so this choice is easy for me. :-)
Another easy choice for me is the atmosphere model. I only use Spectral.
Another easy choice for me is clouds type: I only use spectral or spectral2 (never volumetrics or others).
Another easy choice is secondary suns: I don't use it.
Sky dome lighting gain: always use it.
Many people prefer atmospheres with light balance more towards ambient (20% or 30%). I prefer around 80%, I think the scenes become more vivid (I compensate the darker shadows with the sky dome lighting gain). But this is because, personally, I prefer bright, happy scenes.

With practice and experimentation, you'll discover what you like. Above is what I like, not necessarily the best for you. :-)