Decline DB Press: How Much Decline?

how do i determine how much of a decline i should have judging by my height and weight? also, i wanna bring the dumbbells almost to my lat area and push straight up, or at an angle?

push straight up, decline angle 30-45 degrees, any higher will hit shoulders more

The more of a decline that you have; the more of your tri’s that you will hit. tri/shoulders i mean. i’m just too lazy to hit delete.