mattwnz:

KennyM: I would never nail a deck down, ive seen far to many that have pulled up.
However i think there is some proper decking nails that have barbs that are supposed to stop them pulling out once installed. (think fish hook)

I used 10 x 65 Stainless screw when I did our deck last year, I predrilled but didnt countersink, we only have pine and just drove the screw in until they were in far enough.
I could do that, but my partner couldnt push hard enough to do it (would strip head)

I would recommend a drill bit with the countersunk bit on it already, do it in 1 motion.

That kreg hidden fixing looks good, I would check tho that 140mm isnt too wide to only have a screws right on the edges.

The length of the nails do make a big diffference, as does skew nailing. Galvanising does create a lot of friction, but you can also get grooved ones with larger heads. My main reason for not using screws is cost, as if you have got a large deck like I have, it would cost a substantial amount compared to nails. The bigger problem with decks is deterioration and them getting slippery. Don't ever put pots on decks, as they cause big problems.