the pins are in the wrong place
add a inch to get correct units ?
what do i do with the 8 pcs i have too short ?

When determining the best replacement for your current spiral balances, you have to measure the metal tube portion of your balance only, not the tube and the protruding spiral. For example, a normal S600-28 spiral balance has a 28" tube, but a 29" spiral.
Does your balance touch the window sill, or does it come up short? If it did come up short, can you tell us how by how much? Keep in mind, there are two different spiral tube diameters available. The Series 600 has a 5/8" diameter, and the Series 900 has a 3/8" diameter. Did you order the correct one?