Read the loadout first
Before choosing a target, inspect the skills you have equipped and the resources they use. A target that supports your actual loadout is more useful than a large number selected without context.
Use a measurable gap
The stat planner subtracts your current value from your chosen target. If you enter an observed gain, it can estimate repeated actions under that assumption. Randomness, changing costs and event bonuses are not simulated.
Check the version
The 0.9.0 notes adjusted enemy agility growth on higher difficulties. A target recommended for an older patch is therefore not automatically a current breakpoint.