I haven't gotten around to making a nice board with slots for each hone, and for some reason this setup wasn't obvious to me so I thought I'd share. Front is against a bench dog, back is pressed against the rubber foot of the edge of the bench. It is easy to swap in the different hones, and doesn't scoot around.
(Still figuring out how to put a burr on that card scraper though.)
What I have found about card scrapers:
Any old burr needs to be removed, so hone the edge flat against the stone. Do both sides before doing the edge.
The edge must be square. Think of it like a board, it's got thickness, and that edge face must be flat and square. Any old burr must be removed. If that edge is domed at all, it won't burnish right. So I made a little fixture that's just two pieces of oak held together with screws. 
That way I can hold it perpendicular to a hone to properly flatten it. Or file it if need be.
The burnisher needs to be HARD. Like, file hard. I got a burnishing rod which is quench hardened steel, it works okay. I also bought an Accu-Burr which is carbide, it works pretty well and is a little bit more idiot proof. Even if you don't go with an Accu-Burr, if you're going shopping for a scraper burnisher I'd recommend a carbide one rather than a steel one. Consider that recommendation the opinion of Some Guy On The Internet.