I had to do a midliner on the floor just me and a trolley jack. Apart from being on gravel (used a sheet of ply to get the jack to roll) it was a pretty nice job to do. Given a smoother floor to work on I would probably opt to do it that way again.
It's easy to get arm/back/neck ache reaching up on a ramp/pit.
I remember doing a midliner , two of us , on Xmas eve out side in the snow with the lorry sitting with two wheels on the road and two on the foot path so we could lay in the gutter to do the job , looking out at the snow level with the side bars on the lorry , and the water running down the gutter we were laying in ,,, Luxury .
we had the thing back on the road in under and hour and a half ,,, but it was grim.