Do it right, use some screws, predrill the holes. The whiny know nothings say the screw rust...which they do do......but........this takes many years, longer than most set ups last. Even here, 4-5 years later, I've back out some screws I used that where not even stainless, they where fine, a little corroded, but looked like they'd last another 5-10 years to me. Even the ones where they where buried deep in the soil etc and blackened anaerobic conditions. I've used SS but the plain old coated dry wall screws worked even better. Even 4 years later, no corrosion.
The small amount of oxidized Fe and other metals, so what.
Use the screws, I've never had any issues, the rest is fear mongering.
I've been here and done this for a long long time.