The front should be 18/9 and the back should be 18/ 10 1/2 if they are chrome. They are not as popular as you think. But you might catch one person willing to pay. One person is all you need.
I saw a set almost new for $600 on Ebay shipped. A month ago $1000 new in the box on Craigslist. It's best to sell them separate because no one wants 3 rims. If they are black I will buy them. But I think only the newer Mustangs have Roush black rims. That is what I am holding out for.
new engine,1.7 rocker arms,Pipes exhaust, shorty cats , shorty headers,under drive and overdrive pulleys,4.2 upper plenum, throttle body spacer, cold air intake, stage one clutch, shorty shifter, and tune. 8.8 in storage