This is my take on it.
If you are going to take the time to take in a bird who may very well be with you for many years then just get a bird you know will not have issues or get a baby bird.
It is not worth it to waste your time with a bird who may never be tame.
This may not come across right to everyone and may come across as selfish here but our lives as humans are short and precious and if we are going to take in a companion animal we might as well have the best we can.
I realized this when I wrote that my blue front amazon wanted too much head petting. Many people wrote that they wished they had that problem and their amazon wouldn't even let them pet their head.
I always think about that and the fact that many people have amazons who they can't even trust to shoulder the bird. They are missing so much in my opinion as it is very nice to shoulder my amazon while she sits on my shoulder for hours.
Why would you want to buy a amazon where there is a good chance you may never do this with?
I don't know, that is just my way of thinking.
I do have to wonder what will happen when/if your snuggly, shoulder bird matures into a hands off roommate? There's no way to know if that cute and cuddly baby will stay that way into adulthood or if, as happens with MANY babies, as they mature they will prefer more distance. Sometimes they stay that way permanently, sometimes it is a short lived adjustment period and then they go back to being cuddly, sometimes it is just a seasonal thing. But it happens AND it happens often enough that every owner should know that this drastic relationship change is a possibility.
So, if your bird grows up and prefers a more dignified mode of interaction are you going to be okay with that? Or is this another mature Zon who will wind up evicted from their home simply because they grew out of the cuddly baby stage and didn't live up to their owner's expectations?