When I look at other reports of large kitty attacks, they are more so on women and children. Unlike bears the cats are true carnivores. They are stealthy and size up their prey. This makes it very hard to plan any defence against them. The lady survived because of her friends persistence in helping her. Striking the cat in the head with a BFR worked out for them. The use of the knife not so much because the person wielding it had no training and didn't know the vulnerable areas to strike. Slitting the cats throat taking out an artery and the windpipe would work. The only chemical spray that might work is bear spray and it is likely that everybody would have have been affected by it. There was an attack in California north of me more than 5 years ago. A lady and two men from work were riding there mountain bikes and a large cat attacked the lady. The two men turned tail and pedaled away leaving the lady to fend for herself. If it wasn't for a couple of other mountain bikers coming to her aid, she would have been killed. The girls beat the mountain lion back with there bicycles. When the authorities found and put down the cat, it was discovered that the cat was extremely underweight. You by yourself can't 100% be safe from large cats, especially if you are a small child or lady. You and your friends need to work together if their is an attack. As far as a defensive weapon goes, It appears that you need everybody to be wielding things like BFRs, knives, sticks and a very powerful stun gun.