i throw straight at majority of my spares. if you put any kind of rotation on the ball you are hoping and praying the ball doesnt check up on you or skid out. so you are never exactly sure if you will get the spare or not. if you break your wrist and point your thumb at the spare you are aiming for, which is what pros do, you will have less to worry about when you do go for spares. you wont master it at first, it takes practice. and yes your ball may roll end over end, but it wont hook which is extremely beneficial especially if you bowl on sport shots..