Because I mix up only 1 gallon of ONR, I find that my grit guard becomes useless in the ONR bucket because in a 5 gallon bucket, 1 gallon is about the height (maybe lower?) than the grit guard. And because I swap out mf towels when I use ONR (instead of switching between mitts), there's really no need for a rinse bucket.
You know what I wouldn't mind seeing is a "low profile" grit guard. I have 2 grit guards and most of the time, I end up using both in my rinse bucket instead because it's too tall for the amount of soap solution I mix up.