I am running 12-32 with 6700A RD short cage (SS)and it works. But I only have a 10 tooth difference on my front 2x chainrings. So that is just a 30 tooth max I have.
With a 34/50 double in front I think you would need a Medium Cage RD (GS).
I also have a 30mm hanger... a bit longer than normal and it helps. Chain length is important as well.. also B screw turned in somewhat.