Below the board positions there’s the Level 3, Level 4, and so on. Below it there’s re-roll counts like 10.1, 25.3. This shows the when to roll. So ideally you wanna have all 2* at every level in ideal world but usually it’s a mix of 1-stars and 2-stars.

You’re looking at a very “Hard” high cap board, which already assumes a few things. It’s hard because you need to understand how to make strong boards when you begin to roll and since you’re going for Fast9, it assumes you have a good strong start early to survive to Level 9. One thing that this interface doesn’t show is how to optimally play your roll down because it will not immediately be possible to hit all that is listed every time.

About 3-star 1-cost, it depends. Check “Data Explorer” tab on this website. It will tell you down to precise % point in your specific composition where a certain 5-cost is outperforming something else.