I did it with my restored convertible back in the 80's when I did a chassis off restoration. I measured the rocker heights before removing the chassis to get an approximation of the clearance height needed. When I (well....we being a few guys) rolled the chassis back in as a restored assembly after the body was painted and chassis detailed, the body was supported by the rear wheels (acting pivot point) and each rocker supported with carpet lined 2x4's on hydraulic jacks situated mid-way and slightly above the clearance height measured before. The chassis rear was supported by a heavy duty Sears mechanics dolly to support the tranny side. I used a small section of steel pipe to act as the alignment pin before securing with the chassis rubber and bolts.