When the deep part of the grip is in the center of the bow.
With the only part of your hand is pushing the grip is the crotch of your index finger and thumb and pulling the string from above center it has to be negative tiller.
With my arrow shelf being 1" above center I go 3/16" negative with split finger.
I take several bow to the Tennessee Classic every year and get other people to shoot them while I set back a watch.
I don't ask How it shoots but I get good comments.
My 2 cents.