No 1 for me , notch the up right to stop the braces flying out , notch the peg post to stop the brace slipping down and nail the brace in place top & bottom into the notches with some 6inch galv or sheradized nails or if you feel wealthy .... put in with a big battery drill or a brace & socket that takes a decent quality Phillips etc head some long stainless steel screws such as those found in Screwfix in the decking sections .
You could also use a small auger and use stainless or galv studding & nuts that goes through post & peg .