Drilling C-Can wall - utility outbuilding

Hi. I've been asked by a woman with a small homestead to consider whether I can modify a small C-can that she's acquired for use as a utility building. I'd need to drill holes for fasteners in the can's walls. I have a corded half-inch-drive drill (powerful)... also, for higher rpm, I've got a Makita 18-v cordless.

I'd be using 1/4' carriage bolts. I'm guessing the steel on these cans is pretty tough material. My question is how easy or difficult will the metal be for driving a 5/16" cobalt-steel bit through?  Along with all the materials for the modification, the woman would pay for bits for the task, as beyond 1/4" my cobalts are various random sizes.

Have experience?  Please answer. Thanks.

I think most of these are made from Corten nowadays. Tougher than mild steel, so consider a cobalt bit and go slow. Step drills are nice. Cutting fluid is also advisable to keep things cool.