I use aluminium nails when doing a slate roof, they are a bit easier on a slate ripper and I'm glad I did as when FIL did the ridge tiles on my garage roof for me he managing to crack a couple of tiles in the process.I also used copper nails which is the traditional way but many just use galv now due to the cost but the reality is it made maybe £70 difference on my 85m2 roof
@julianf
If you and your partner fancy an interesting day out I did my Introduction to Lime course with these guys.....