Whether you're spare ball is cheap or not, it should not hook...that's the reason it's called a spare ball. It should have a polyurethane (which can hook a bit on really dry lanes) or plastic coverstock (which will almost never hook unless you are really trying to do so).
My old
Storm spare which I'm about to replace with a new
Storm Spare is polyurethane, and I'm still about 85% on the 7 pin, only missing when I tug it or overshoot or whatever. If it does move on me, it's barely noticeable (maybe a 1/2 to 1 board even on burned up lanes. And I rarely 'break' my wrist...I just stay behind the ball all the way through the shot as opposed to wrapping around it.
By the way, fingertip for everything you drill...it just makes sense.