Chris responds to Hannah by saying, "Let me see if I can shed better light on that."

The phrase "Let me see if I can shed (shed) better light on something" means "I'm going to try to explain something better,"

or "I will try to help you understand something better."

That is to "shed more light," or "better light" on something.

In this case, it means that Chris is going to offer another explanation of what he said earlier, using more detail and, perhaps, different words.

Chris says, "Although colors may not be as important to consumers, we are of the opinion that having more variety will increase sales."

"To be of the opinion that…" is a very formal phrase that means to believe, to think, or to have an opinion that something is true.

Chris could simply say "we think that having more variety will increase sales," and it would be the same thing - the same meaning,

but it's more formal to say "we are of the opinion that having more variety will increase sales."

Hannah interrupts Chris by saying, "Is that the only reason?" before he finishes speaking.

So, Hannah is interrupting, or talking, while Chris is trying to talk.

Of course, Chris doesn't like being interrupted, so he says politely back to Hannah, "Please let me finish my thought."

"To finish your thought" means to finish talking about something,

or to say everything that you think about something without interruption - without someone else speaking while you are speaking.

When Chris says "Please let me finish my thought," then, he means "Please let me continue and finish what I am saying."