Welcome to RAD mate,
If you don't have any luck finding a shim you should be able to make one from a beer can til you find one!
Get some pics up of your Reflex, you will need a photobucket or similar hosting account. Keep a look put for parts on here and Ebay, you will have it built in no time.
Whilst the Ally hub tuffs will look nice they are a tiny bit early for an Aero Reflex as they came out in 85 when Skyways were crossing over to sealed bearings. A pair of Aero Zytec mags would be ideal for the frame...