I went over the area to be leaded with a wire brush to make sure it was smooth/clean before applying the solder paste.
After filing the lead flat. This is an odd area to shape, the upper half is slightly concave in both directions so the flat file could only do so much shaping.
So I sanded it with 36 grit to finish shaping it. I know you're not supposed to sand lead, but the 36 grit is so rough that it doesn't make fine dust particles. I was wearing a mask of course.
The 36 grit lead "dust", almost big enough to be called shavings. This isn't small/light enough to float around in the air so I felt ok about sanding with 36 grit.