What I would like to do is share with you what I would do.
1. Your grey by nature is shy and a amazon by nature is very out going
2. This is your greys home and the amazon is a visitor.
3. Make sure your grey always has top billing, First to be uncovered, First to be fed and watered and first out of the cage, and last to go back in his/her cage and last to be covered at bed time. Remember this is greys home first and they should keep their number one spot.
4. I don`t know how well you know this amazon so make sure you can handle be for ever letting it out of its cage so if something goes wrong you can handle the zon with out fear of being bitten.
5. Supervision, supervision, supervision.
I hope this helps.
Let them see each other in their cage before introducing them to each other and se how it goes.