I didnt have a riser block or limb blank for the pics so I just used what was laying around for demo.
This is not a width dependent jig. It will go from 2" on down and even mate a riser to a limb of another width.
So you mount and center jig onto riser block snug bolts and drill. Place limb blank onto jig, center and check alignment with string down riser too. Make sure limb butt stays on centerline while you adjust bolts to move limb tip to desired position.Snug bolts on limb and remove jig from riser block and drill.. Repeat on other side..
When making hole pattern of choice, if your holes are not all perfectly dead center it wont matter because it lines up.