rdrp brass bulkhead help

[Stickygeko]

Just received this from mb today. It is a multi option 25°/30° inserts but ive no idea which way to put the inserts...they aren't marked at all and there's no instructions. basically 4 inserts. All have a notch at the bottom...Therefore you put them all at the bottom...all at the top or a mixture of rear bottom front top and vice versa...Please help my setting my car normally has is 30°