I've been sprayer and sprayee, with Cap-Stun and First Defense conical fog OC. I've sprayed dogs the most, and they typically aren't really fond of the stuff. The dogs I've had to spray all reacted immediately, but some came back right away, more angry than before, while others didn't come back. The fog is rather sensitive to wind or breeze, while the stream style is less sensitive.
For decontamination, try using cool water and baby shampoo. The baby shampoo does wonders for soothing the burning itchies in your eyeballs and does a decent job of neutralizing the OC on the skin as well.