All Metal Core pcb have used a combination of routing and v-scoring. Small drills are too brittle to drill mouse bites in aluminum.

I will also choose V-score. You can then either use a jig to break the boards apart or, if your volume is high, purchase a purpose-built de-panalize machine.

V-cut is a good way to use. I would put two boards back to back,so that not straight side for both of them would be towards outside.