<VV> Rotisserie for a Greenbrier

[D. Monasterio]

Folks,
    I am in the processing of restoring my recently acquired Greenbrier 64 and, in order to work on an easier way, I am making a rotisserie but, I have only a vague idea of the best balanced rotating axle for an empty shell (no powertrain, suspensions,seats, etc.) Do somebody knows how high over the rear and front bumpers are the best points ? 
    
    Thanks a lot for any answer

    Daniel Monasterio