As I said I have seen only shepherds to use this kind of knife. So I have no idea how you can hold it in a combat situation.
These shepherds were very fast and I noticed that they were changing the grip a lot of times to flay the goats. I suppose that there are few techniques to hold it without the risk to cut your fingers. But dead goats dont fight back
The T-spine is the oldest type, but we can call authentic also the normal spines as far they have a hand forged and real blade, like the type Tim show us it the other post.