the biggest issue with drilling holes in acrylic sheets is that the acrylic can crack as the drill bit exits the hole.
If may sound strange, but there is a trick we use to make sure this does not happen.
Using a normal battery or electric drill, run the drill in REVERSE at the highest speed possible with a normal drill bit. Apply firm pressure as you push the bit through the acrylic. This will melt the plastic rather than chip it.
It takes a little longer, but will give you perfect holes without cracking.