Thinking more on this, I guess triggering on leading edge would maybe not work well in conjunction with the accent functionality?

Please do! I did some tests with ADDAC104 triggered at same time as Kickain and with ADDAC104 audio routed through Kickain: KickainLatency.wav Both modules triggered from NerdSEQ. First four bars shows how the latency is (around 8ms!) next four bars has triggers to ADDAC104 delayed to compensate. As for avoiding double triggers - why? Let the user decide how fast they want to trigger.. it might be cool to trigger at audio rates. Trigger at 3V on leading edge along with a couple of volts of hysteresis in trigger detection function is enough to avoid unwanted double triggering. [edit] Did some experimenting with triggering kick as far into audio rate as is currently possible - it is indeed cool. [/edit]

I tested with NerdSEQ - 5ms trigger is actually a bit shorter (~4.93ms) and doesn't trigger Kickain. 10ms trigger length (actually ~9.79ms) and above triggers OK.