I am curious as to what kind of an AMEX you have that transfers to SR. If it transfers to Qualiflyer, and then you get tickets, you habd better start now, because Qualiflyer took forever for me, and the plane left without the miles.

Steerage is Steerage in US to Europe in all my experiences. AF, BA, UA, AA, LH, SR, all are interested in the most cost effective way to transport the cargo from point A to point B. The differences are small, compared to the discomfort.

Book early, as the plane may sell out early.