I use about 1/3 water to 2/3 vinegar. Rough estimate, though.
I like it because it works, and once it dries on tile it turns the pee stains (yellow/brown) to a white color. Less noticeable in the end, which is very nice!
I use straight peroxide. It cleans well and will bleach the stains without leaving a harmful residue or a smell since when exposed to the air, it breaks sown into water.