The method I use for flush rivets is the heated brass tube in primer technique. I used the smallest brass tube I could get, and mounted in my trim iron. I also put a 90 degree bend in the tube to make it more comfortable. I prefer to mark off all the rivets first, making proper spacing adjustments so intersecting rivet lines properly meet. After burning them in, I lightly sand with 400 grit to knock off any rough edges.

Scott