Sphere Break
Solution
Score:
Coin Count
Multiplier
Echo targets
Priority
This tool was developed after many frustrating hours trying to beat the Sphere Break Elites. Let me be clear - it will not guarantee you a victory every time you play, as some luck is needed against some opponents (especially the Elites, where a random core-1 in the middle of the game will annihilate your chances of a victory). However, it will allow you to quickly explore solutions that can keep your Echo streaks alive.
Sphere break is a mini-game in FFX-2, just like card games in the past FFs. Basically, Sphere break is a game that's all about sums and multiplications. Instead of following the old system of card games, in which you can win easily if you have got some rare cards in your hand. This requires you to use a little brains. Sphere break is a race against the clock to create multiples of the core sphere's core number by combining numbers of the 16 coins on the board. Confusing? Well, like Shinra said, "Once you get the elementary, you will get the hang of it."
I have set what I believe to be good targets as defaults, so you don't need to change them. If you want to toy with them, just know that I've caped the Coin Count Echo value to 6 because the algorithm I am using becomes very slow starting at 6. If you are a developer and want to contribute, feel free to implement a better algorithm.
The same advice applies to the Advanced options box. The only one I would consider toying with is the Maximize border coin count option: turn it off when you feel you will be running out of border coins soon (rule of thumb: < 30% left).
For low level opponents, it doesn't really matter as long as you have at least one Echo coin, and different numbers in the middle. I usually aim 3-6, but it doesn't really matter. You want to focus on keeping one Echo streak alive, so those will give you different options.
For Elites, I usually pick both Echo coins. You want to keep both streaks alive as much as possible, and balance how many border coins and 9s you use - you will get a feel for it after a few games. For the remaining coins, Quota multipliers are great, but if they are both high, you might need to change the default Count/Multiplier targets.
More strategies
I managed to beat the elites using your tool by keeping the default options except prioritising multiplier and setting it to 2. I used the coins 1, 2, 4 and 6 and the only trait required was multiplier echo on one coin.
This way the chain will keep going even if you get a 1 in the core and coin count echo did not seem to matter using this strategy.
Don't give up! A fair amount of luck is needed, even with this tool, to beat the Elites. The only way to beat those opponents is to build very long Echo streaks and an Echo-destroying core number (e.g. 1) between turns 12-18 almost always means you are going to lose the game.
I've beaten all three of them using the default settings that I've set above, and playing with the Maximize border coin count option when I felt I was running low on border coins. I also recommend using both the Coin Count Echo and the Multiplier Echo. You probably won't be able to keep both alive for very long, but every point counts.
No, but you are free to do it! Just fork the project and open a PR if you feel it would benefit everyone!