i have a drift of 3 boards left and my release is 7 boards right of the inside of my sliding foot so using the inside of my sliding foot i stand 4 boards left of where i want it to lay down.
all single pin and cluster spares (excluding headpin and 5pins) i use a strait shot with a plastic ball
5 pins- strike line
head pin - strike line
3 pin - 4 boards right of 23rd board (im right handed so from the right)
2 pin - 4 boards right of 17th
4 pin - 4 boards right of 14th
6 pin - 4 boards right of 26th
7 pin - 4 boards right of 11th
8 pin - 4 boards right of 17th
9 pin - 4 boards right of 23rd
10pin - 4 boards right of 29th
i use the mark of 4th/centre arrow to
to pick up multipin spares remember that the pin closest to you is key to hit if the pin directly behind it is left move an additional board right of the key pin board but if its to the right of the keypin move an additional left of the keypin shot.
if its a cluster like the bucket the best way is to for me to stand 4 boards right of 16th so my ball has a bit more power and carry into the spare and have less chance of leaving the 8 pin.
If you are leaving the headpin do you really want to use your strike line?