I would do some natural branches with varying diameter ranging from 1.5 inch diameter down to .75 inch or even .5 inch diameter. I've taken to providing all my amazons with one perch that has a much smaller diameter than is typically recommended for their size and the bottoms of their feet are much better for it. Most of their perches are in the right ball park if their foot curls about 3/4ths of the way around the perch. I usually start out a new bird with the dowl that comes with the original cage, plus 1 or 2 bolt on 8-10 inch long branch perches. Once I get the bird home, I make adjustments from there.