As very hard products have become more popular on the market, I have noticed many seem to prefer using an L-cleat nailer, instead of a stapler. Well, not really thinking, I just wanted a decent floor nailer for a good price. I found a Freeman PDX50C 3-in-1 nailer on Ebay. It basically shoots cleats and staples.

What I never really gave a lot of thought to, is which kind of nail is nest for Doug Fir?

I do a bit of wood working as a hobby, and Fir being a softwood, I can't help but think L-cleats would be best. (Maybe T's?) The reason is that when you fire a double nail/staple side-by-side like that, the potential for splitting the tongue would seem to be much higher from my own experience of building with Fir. Thus, one hole from the nail would be preferred. Correct me if I'm wrong on this.

So, if one hole form a nail would be best, is a 16g nail a bit too thick? Maybe 18g would be best? Would splitting also be a potential issue with standard 16g cleats? Dunno.

Any thoughts on this would be greatly appreciated.

I use staples for fir porches. The staples hold very well. I like that they are made from galvanized wire.
P nails made from stainless steel can be ordered, I have heard.