If you are cooking any animal with a spine then a back brace is recommended. This goes through the back of the animal around the spine and holds the carcass to the skewer. This eliminates the animal bowing while cooking.
Stainless steel disk assists in affixing gyros onto your skewer. Just squeeze your meat in between two disks and they work as well as a prong/spike, only it’s easier to carve the meat because there aren’t any spikes to avoid.