Nice wrench, I tried that myself. But with a hardtop. It didn't exactly want to work.
I lifted the front off the pan with my engine lift. Put a peice of steel, I could have used a 2x4, across two saw horses, then I raised the rear with the engine lift. I did that to install my water lines.
You can kinda see the engine lift in the back, not the best picture, but you get the idea.