Lynn Park former Trigo owner told me this on the phone:
1. Tighten spinner.
2. On a wing, drill 2 small holes.
3. On the spoke directly straight in, drill one small hole.
4. Apply safety wire thru spinner, twist w tool the length to the spoke.
5. Run one wire thru the hole in the spoke.
6. Twist again.
7. Cut off excess.
8. Fold second twist under the spoke.
Result, if the spinner moves either way, you can easily spot it.
If you look close to this image, you can see the "straight in" wire at the 1 o'clock position.
PS
I witnessed Vintage Sports Car Races and the Cobra racing used no safety wire. Food for thought.