I made my own drawknife out of an old lawn mower blade and put the handles more straight out like a rolling pin with about a 45deg. angle on it. That allows me to draw/cut, but also use straight up and down to scrape. It works great for scraping and I can work down a ring fairly quick, but when I get close like one thin ring above the one I'm chasing I switch over to a long fillet knife and scrape easy as she goes from there.
I know what you are saying about Osage. The knot areas are the worst and sometimes the rings start out big and maybe 1/8" thick on one end, but when you get to the other end you can hardly see the seperations. It's a real chore, but keep working at it, it'll get there.
I'm getting ready to start roughing in another one this morning, so I'll be in your boat soon enough Don.
Good Luck!