first up, you need to be a bit more specific as to which bushes you are actually after

the tca bushes are all the same, the one that vary in thickness are the arb to body ones

they come in 3 sizes, 24mm, 26mm and 28mm for the sierra and, before you start rushing to buy them, certain sizes also require the clamps for the coresponding bush

if you were to attempt to fit bushes from, say, a granada that came with the same arb (be they 26 or 28mm) you might find that the clamps are physically bigger or smaller than the ones you have one at themoment

even though the holes int he chassis are constant, due to the difference in sixe od the clamp that holds it in place, the bush will also be that much bigger/smaller

it would be much easier to measure the arb in situ (on a straight bit, not a bent bit of the arb) and then get bushes for the sierra for that size rather than guestimate as it's a favorite trick of ford to swap between the 26 and 28mm versions through the production

you are probably looking at the 28mm versions but there is always the possibility it'll be the 26mm versions too