Personally I use both the whole area between both joints. I press that bone against my jaw bone.
Anchors can be tricky because every one has different shaped faces, jaw lines and size hands. Anything new will feel unusual at first and be hard to repeat until you have enough repetitions for it to become second nature.
Spend a couple days at blank bale trying out different anchors. The most important thing is that you have bone one bone contact and good alignment.