Interesting video. I would be interested which timer/processor you used for this purpose?
What I used is led and buzzer which is control with relay with timer for 10 sec delay, so no three marktimes and no ignition switch contact check.
It’s an ATtiny85 based processor, they’re good because they’re easily programmable and reprogrammable. I've parameterised the timings so they’re easily changeable but I've found these timings work ok.
I had thought about making a small batch of these if there was any interest.