How do I know if my minions have enough accuracy?

Is Grave Pact enough? Do I need the nodes in the big minion wheel? Maybe I do for this build, but not for that build. Maybe some minions need more accuracy than others. Maybe these minions get +2 levels from my helm, so their accuracy is fine, but my other minions actually do need accuracy.

How can I know if the minions I'm using (on whatever build I'm using them on) need more accuracy?

Use Path of Building. It has almost all the relevant minion stats and can give you a much better idea of how much damage they actually deal than the tooltips ingame, and it does have the minion accuracy values.