I set mine up with a little tube on the bottom of the tank. I can hook it up to a pump and syphon all the water out from the bottom then put the tube back in tucked down until the next time I need to drain water out. I use a misting system with distilled water. Personally I don't like drilling any tank since it usually reduces the value and you only have one shot to get it right. If you do drill it practice a few times on inexpensive glass.
Let us know how it turns out!