You have posted many similar questions in the past. Did you understand the answers from the experts? It appears that you have digested the explanations because you kept asking the same questions. " Right when " and " just as " are practically interchangeable 99% of the time. I'd say, " just as " is more common. Right when means the same as "when". Right - emphasize the moment, "when". That's
They're all right. Lo, seven years later, I wonder if you have the same question. It just depends on whether they agree with the tense you're using elsewhere in the same paragraph/document.