If I am waterproofing, I look for products that allow the item to breathe. I have had good luck with the function of these sprays, though their chemical scent sends me into a severe headache zone. I let the items air outside of the house for quite awhile and find it does dissipate after a day or two. Don't recommend spraying inside. Can't remember brand names.
I also just tried boot cream and oil that my equestrian daughter used on riding gear, not sure that it would "completely" waterproof, but big refresher of leather and they add protection while renewing the finish without such a caustic odor.