If I read this right, you've already owned an amazon. Because you said 'another' amazon.
As long as you've had the experience, done your homework, are aware of the expenses and time involved; I say go for it!
The nice thing is, she's already 30 years old. So, she probably wont out-live you. I think all you need is the above mentioned preparation, and you'll do just fine. It's also nice to know how she acts around other parrots. I reccomend that you spend more time around her to get an idea of what she's really like before you decide for sure to go ahead with it.
The usual advice given in your situation is "don't get another parrot for your parrot-- only get one if you really want one." It sounds to me like you're enthusiastic about having another Amazon, and I know what I would want to do in your situation. It seems like April can get along with another parrot; now, the key is finding a second Amazon who will be compatible with April. Good luck, whatever you decide to do!
It is also a great situation for the parrot. The overall stress level of the bird is reduced when he’s adopted by an individual who keeps his routine as similar to what he’s been accustomed to. He’ll appreciate you not changing his diet drastically or adjusting any of his well-established habits too radically. Overall, the stress levels for the two of you will be reduced.
Adopting a bird who you’ve already met and whose background and habits you know will increase the odds that you’ll have a successful adoption process.