[zipzip]

I used the jacks in the wheel dollies to support the frame as I was prepping it. The problem I had was that 4 points do not make a plane, so one was always loose. Once the engine and rear end were in, it got a lot more stable.

I'd say if you were handy with a welder, you could weld a raised support on top of the dollies to lift the car higher. Match the height with the max lift you get off of the jack and voila.