Well, I haven't answered any of your posts because I don't have an Eccie and know nothing about them. I do, however, trick train my birds so I can talk about that.
I have two Alexandrine parakeets called Barney and Madge. They are a bit over a year old (I got them in April last year). Both birds enjoyed playing with whiffle balls (the little openwork ones with bells inside), so I used those assuming they were well received. In our case, that was a good decision. I had never heard of touch training back then so I proceeded like this:
1. 'Play ball, Barney' - touch the ball to his bill - give a food reward.
2. Within five minutes, he'd worked out that touching the ball earned a reward, so he was earnestly pecking the ball all over the table and then turning to me for his reward. Great!
3. After a week or so of this, I began saying 'Fetch' instead and holding my hand under the ball if he picked it up in his bill. The idea was for me to catch the ball if he happened to drop it (which, of course, he eventually did). Then I rewarded him. It took one session of about fifteen minutes for Barney to catch on.
4. Next, I got ten large, colourful acrylic beads which were easy for Barney to pick up. I just said 'Fetch' and pointed to the beads and he obliged. This shows he can extrapolate his learning from one object to another. Yay Barn!
Parrots are very bright and it doesn't take much for them to learn
provided you make it bleedingly obvious what you want of them. If your bird doesn't catch on as quickly as you'd hoped, stop and think hard about how you're teaching him and what your actions and commands appear like to him. Barney got a bit confused about the difference between 'play ball' and 'fetch', so rather than confuse him by starting again, I got a different-looking ball for each activity. No probs after that.
I have taught Madge in exactly the same way I taught Barney but she has been significantly delayed in the speed with which she picks things up. It's a personality thing: Madge is just not as interested (or as greedy) as Barney is. On the other hand, it is always Madge who figures out how to use the new foraging toy or how to dismantle the new chewy toy. She's an explorer and free spirit.
I have tried trick training with my rather older Galah, Dominic. While he's happy to try, he gets impatient very quickly and gives up after about five minutes. I know when he's sick of trick training when he takes a substantial chunk of my flesh in his bill, chomps down hard and twists through about 90º. Then I stop.
It is very important not to overtrain your bird. Watch for signs that he's lost interest, find an opportunity to ask something of him worthy of a reward (eg. 'Step up') and stop. Twenty minutes would be the absolute maximum training period for any bird. Always end training on a positive note like this and your bird will have happy memories of training and be willing for the next lesson.
If your Eccie is playing aggressively with his balls

EEK

, then I'd think they were the perfect tool to use for training. But that's just me. All you can do is try and see what your bird likes. I hope this has been helpful to you?