Be very cautious hammering on your airframe because you can easily cause distortions. Use a pair of pinchers of the type used to squeeze ear clamps to cut the back of the rivet, pull out the stem, then drill carefully. There is one style of pincher that has an off-set jaw which pinches on the end as well as the side which are good for accessing tight spots.
Bikeservice Motorcycle Double Ear Clamp Pliers, BS2904 | eBay