Microneedling using 1.5-2mm depth: how frequently?

I have acne scars of all types (rolling, boxcar and some toothpick). Recently, I have purchased a mechanical microneedling device (like a tattoo machine type action, so the pain is tolerable with single-use needle cartridges and no numbing). My questions: -How often can I do this without causing more harm than good? -How close can I come to the under-eye wrinkled area if I reduce depth? Thanks!