Regarding bottle jacks, I built these jacking rings into my slider mount points..
[Linked Image]

pardon the big pic.... <img src="/forums/images/graemlins/shiner.gif" alt="" />

Just another option to have handy... to be able to use this with a bottle jack, similar to the way hilifts are used to pivot a vehicle over out of a deep rut.

Also makes a more secure jacking point for any situation as the tip of the bottle jack can't slip off the frame and go up into the floor or what ever nearby..