Being an old sheety I would recommend the following.
1. Make sure you expose the rivet head (especially csk) remove paint.
2. If RH file a flat on the head.
3. Centre punch the rivet head, pref with dolly behind rivet tail.
4. Use 3/32 start drill.
5. Then use a drill slightly smaller than original rivet dia.
6. Drill head off
7. Use rivet dolly next to rivet tail and punch rivet tail out.
Obviously if you have thousands of rivets to remove it can be exhaustive, if you are removing the skin you can usually skip steps 1-4. Based on experience this does allow you to occasionally move off the rivet, I personally support the drill with my hand on the skin or member and slowly start the drill with the drill in step 5 as it doesn't matter if you damage any skin material or part that will be scrapped.
To avoid the drill running right through the skin and possibly damaging parts or cables behind the skin when drilling blind. I used to wrap solder around the drill bit from the chuck to the tip exposing just about 5-10 mm of the drill tip. The solder would prevent the drill going straight through the skin and the solder was soft enough not to cause any damage.
I miss the sheet metal work side of things and spent hours in my apprenticeship drilling rivets
Hope this helps, but practice makes perfect
