Yeah doesn't matter how you position your fingers as long as the muscles in your hand are relaxed. Typically a relaxed hand will kind of form a circle and give you that security of holding it but your not. Alot of people who do open hand force their fingers outward. When I'm showing people to do it for the first time I ask them to (without the bow in hand) hold their hand like they are shooting and wiggle their fingers and then let their fingers and all their hand muscles go limp. Your hand will naturally form a half circle with ur thumb. Then I have them do it when they get their bow back.