From the look of the photo the trailing edge of the dérailleur cage is closer to the big ring than the front of the cage by several mm's. Is this correct? For a start I'd lower the dérailleur until the rear cage is about 1mm above the chain ring - looks like it's 5mm above right now. If you still have shifting issues, remove the dérailleur and using a large crescent wrench, tweak the brazeon a little. Shouldn't hurt anything if the brazing is sound. Worse thing that can happen is the hanger cheeses off which will be no loss - you can go with a clamp on.