There was a thread about this last Summer. One opinion I remember was to get a hand-held shower attachment and remove the water flow adjuster so the pressure is higher. I just use my hand held in the tub if/when I have to bathe the dogs. The dogs don't fight me and even my foster had a bath a week after I got him(he didn't know or trust me at all~I just went slow and intro'd the water before putting him in the tub) never a problem w/ rinsing or getting the water where I want it to go or not go!
I think we are an over advertised/ over gadgety society and this is one example. My opinion take a pass and spend your $ on a training class~we can never train enough!)