Rokeby -
I'm not answering your question, but I use tirerack.com to figure out OEM tire sizes. A 1987 Oldsmobile Cutlass Ciera had 185/75-14 tires. I googled "oem hubcap" and eventually ended up here for the Ciera :
Oldsmobile Ciera hubcaps, Olds Ciera wheel covers. Hubcap Heaven and Wheels
Question: How are you going to fit hubcaps onto your alloys? I thought hubcaps were only for steelies.
CarloSW2