Use a hard‑wired clock source and lock both the synth and laser controller to it. Keep the loop buffer small—no more than a few bars—so you can update it in under a millisecond. Run the sequencing on a real‑time DSP or an FPGA; that guarantees deterministic timing. Add a small safety margin in the firmware so any minor jitter gets smoothed out before it reaches the laser. Finally, test with a simple 4‑bar loop first, then gradually add layers; that keeps the groove intact while you scale the speed.