I think the sweetness of the Pepsi cancels out the acidity of the Coke. You should be safe mixing the two, but you might want to verify that with a certified high fructose corn syrupologist.
And I definitely second the concerns everyone else is having. I think it borders on harrassment when someone openly says "Please, I am not comfortable with your type of advice" and the poster that the polite request is aimed at keeps coming back with more and more quotes and lists and questions and hints of support.
((((((((((PattyHavingAHardTime))))))))))