Returning the Product Name of the first three products without sales, per customer

Hello,

I've got rows that are sorted by products sales, best to worst, and then columns with each customer's sales for those products in the columns. I'm trying to find out how to return the top three products without sales in them for each customer. I think it's some kind of array formula, but I'm not sure how to work.

I've attached a file to show what I mean (some color coding added to indicate relationships)

Thanks for any help with this,

Daniel