John, they are available in many different sizes , petrol and diesel, and some are directional ie drive themselves forwards or backwards. Compacting in 100mm layers is good practice, obviously the less depth you try to compact in a pass the better results you will get.
These are quite expensive pieces of kit to buy, and a very limited market to sell on, I'd suggest looking at hire for as much as you will use one. You can dig out all your paths, place the stone, then whack another day in one hit at the end of the job.
Do initial compaction by driving your digger on them !
Are these vehicle or pedestrian tracks ?