floating the aluminum

[zen]

Hi guys and gals.
I don't post much but read this forum almost every day. It can get addicting. Especially when your in the middle of a build.
So I'm almost ready to put on the aluminum. I have decided to go with the majority and float the aluminum.
My question is this. If I were to put three screws in the roof say one foot apart , would it be OK if the aluminum expands and contracts ??
Would it take from the looks for the tear?

Opinions are welcome.
Thanks in advance.
Daniel
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