Recovering Shed Roof Felt - Galv nails or Adhesive

My shed roof felt needs replacing.

Going to replace the OSB boarding with Plyboard (2.4 x 1.2 x 2).

So I'm using B&Q Green felt to cover the roof.

But which would be best to attach the felt, Galv nails or felt Adhesive.

If adhesive is suggested, how much would cover the roof. 1 or 2 ltrs. ??

Thanks

I always use nails but often because im not replacing the boarding and its damp/dirty. If your putting on nice dry clean boards then adhesive might be good. I'd imagine you'd need more than a litre though. more like 5 at a guess. hard to work with at this time of year too perhaps.

I used bitumen to bond the under felt to my shed roof. I also used bitumen for laying the mineral felt over the under felt, but also hammered galv clout nails through as well. I was uncomfortable putting nails through the felt, just seems wrong, but the felt is supposed to seal around the nails. I haven't had any leaks, but I guess the bitumen is giving an added seal?

I laid the under felt vertically so it was going up one side of the roof, over the top and down the other side. I then laid the mineral felt horizontally along the length of the roof.

Why not use torch felt?