Safety wire is great to stab yourself on - ironically called safety wire. Plus takes time and a little skill, but easy to adapt to various applications. In a jam you can use it as a replacement for a clip.
Your track should have a list of required spots.
Anything on the front steering.
Steering wheel to hub
Steering shaft to hub and chassis
King Pins, Front axles, Tie rod ends, Pedals
Weights are double nutted at our track.
I like the grooved hardware for clips
Here are some examples:
Keep in mind these a only help retain a loose nut. It won’t help much on a broken bolt. If you keep getting a loose nut it is time to replace the fasteners.
I carry a decent amount of them as spares. Relatively cheap.