I can’t seem to find much information on the uses or preferred uses of mechanical soil compaction devices.  You know, the  one kind is sometimes called a jumping jack or an elephants foot and the other type is kind of a vibrating sled sort of thing. 

In a few days I’m going to need to rent such a device to compact 3/4″ and less fill that will be under my new place.  I was going to use the vibrating sled type machine, but one of the local back-hoe guys told me I should use the jumping jack type.  I’ll be building up about two feet of dampened fill in 4′ to 6″ lifts.

Can anyone offer a quick description of when to use either type OR point me in the direction of the right link to read?  Thanks!