Not to pick nits, but in this case the term is synchronization, not timing. Just pull back and you'll feel the bump-bump at full draw if it's out of synch. Tighten one buss until a you feel a single bump as you hit the wall.

On my Dually, the cams don't align exactly the same against the limbs at rest (very close, however), but they're in synch at full draw.