Salt for 18 hours with juniper and thyme. Something like 200g salt, 100g of sugar, 15g instacure. I don't normally measure out the thyme or juniper but go pretty easy on the juniper if you use it.
Rinse off the salt. I just use softened duck fat and rub it in as needed, it's probably about 50g per leg I would imagine. I normally do two to a bag, but if the legs are small or you have bigger bags you can probably fit in more. I do 68c for 24 hours.
I don't know about how long they'll last using that method, someone else can probably answer it though.