After building a Night Heron Single and a Night Heron Double with no staples and some very complicated clamping arrangements, I decided to make life easier for myself on my third kayak.
As I don't have a stapler, I settled on the crude but effective method of nailing anything to the forms if it looked as if it might move.
I knew from experience that dents could be significantly reduced in timber by carefully applying moist heat.
After I removed the nails, I tried both methods of swelling the timber around the hole. On some I used my wife's iron with a damp cloth and on others I applied a couple of drops of water and used the heat gun. Both methods were equally effective.
The sequence of photos shows 1) the nail, 2) the hole, 3) after swelling and planing and 4) after glassing.
I think the last photo is the same hole. It took me a while to find it.
I would expect that because staples are so much thinner than the nails I was using, the same technique would make the staple holes near enough to invisible.
I might have to get myself a stapler.