I have a CAT and a SWAT-T. Like the multifunction of the SWAT-T and have personally used it as a wrap when I broke my tibia. A coworker had a severe cut to his arm. Another coworker tried to use a SWAT-T, but it got bloody right away and he couldn't get good compression because it got so slick. A CAT was then attempted and successfully stopped the bleeding. Doc said it would have been questionable if he would have made it without the CAT.
I don't remember he specific percentage, but I think it's over 40% of leg wounds that require two tourniquets to completely stop blood flow. Whichever one you choose, placement should be high on the limb, and make sure there aren't things in pockets or thick clothing that will prevent the tourniquet from being effective.
As others have said, make sure you practice applying a tourniquet with a trainer and not the one for an emergency. Also practice applying it one handed.
Hope you never have to use it other than training!