Unless im missing something about the design, theres a fairly common bit already on the market that works for this, and Id assume most auto shops already have laying around. My dewalt 50 piece came with one…
Bit looks like [This](Best Way Tools Spanner #8 X 1 in. L Spanner Tamper-Proof Security Bit S2 Tool Steel 1 pc Mfr# B86822 - Ace Hardware share.google/KHdg0HfO6zC9bab9O)