For something that is done only once per week I don't see the need to perform any optimizations. Instead you should focus on what is maintainable and understandable both for you and whoever will maintain the solution in the future.
As I understand it the performance side of things stands like this for accessing Excel data.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.