Ewest, the power washer sounds like a really good idea, I have a pretty big one I can borrow from work and I have well water so chlorine won't be a problem. I'll post when I actually try it.
Kent, it seems to me that #4 is pretty small. #2 or #1 would do a better job at staying in place. A grass strip would do wonders for filtering out debris. There is geotextile fabric available that allows the grass to grow through that can withstand whitewater-volumes of water. Bretski posted about it in the planning stages at his place for use in a swale. If you decide to add more limestone, seriously consider the geotextile underlayment and the slinger truck.
