I got to run a lot of Epic Battles this week and I could not find much help on good ways to spend points. A minion ended up sending me this pic, and it helped me a lot.
The max amount of points you can get is 216. As you can see, you can not fill out everything in the chart.
I recommend spending points in the early tier that you are focusing to make the ranks go up faster for less. Then start spending points in key areas to get to the end bonus you want.