I agree with Diablo - your usual grade 5 bolt is fine.
However, if you really want good stuff go for
aircraft quality hardware. Call your local airport
fixed base operator's service operation and find
out where they get it - or look on the net. I used
to use it on my race cars but that was a while
ago so I don't have a current source.

As for safety wiring - you again should look at
aircraft or race car practice. They use a safety
wire pliers which spins the wire - something like
a "yankee screwdriver". You also need hardware with
holes in the bolt heads to take the wire. Again
aircraft stuff has these available.

But again - don't think you really need all this stuff
Bruce