It may be due to lighting in your pics, but it looks like you have some random sand scratches on the frame. Even though the rust will generally fill 320gr scratches and make for a nice smooth surface, I always make sure to sand parallel with the slide rails. I use w/d sandpaper on a small block with a few drops of tool oil, turning and changing the paper frequently.
After that I thoroughly clean in the ultrasonic on the hot setting and then dry with a heat gun or hair dryer. Then it soaks in a container of acetone for a day or so before bluing. After this, don't handle the parts w/o gloves on.
For carding, I use 0000 steel wool that's been soaked in acetone. For hard to reach places, a soft stainless brush works well. After carding, the parts go back in the acetone bath for a short soak before applying the acid again.
Your biggest issue right now will be getting a good coat of rust to form without a sweat box. If it rusts too slowly, put a few inches of hot water in a bathtub and hang the parts from the curtain rod. Close the door and hope the wife doesn't notice! With this method, you should be able to get a couple rust cycles per day. Don't worry too much if the finish looks uneven, it will look better after a few cycles.
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