Rollie Free rode a Vincent Black Lightning. This was a race version of the Vincent Black Shadow C (sometimes referred to as a "3"). It was the same as the shadow with plates, seat, lights and other small changes. Rollie's Lightning was further stripped and modified.
For wind tunnel testing, any late-model Black Shadow stripped to an equivalent level of bodywork should be close. Have to find a rider with the right amount of "ponch" to create the correct upper body and leg angle...