fullmetal,
WELCOME TO THE AWS WELDING FORUM!!
I know some of the other guys here have a lot more experience with your question than I do.
You should find your answers within D1.1 Clause 4 for welding and testing materials for a PQR. Right off the top of my head I believe what you state about the alum will be the same for the 513 as well. I did not look this up, Books not handy at the moment. I don't do PQR's often. That's what I have books for, guidance when needed.
Hope some of the others chime in soon with more complete info for you.
Again, welcome.
Have a Great Day, Brent