Cutter and inserts for 1" grow cubes

This is for growing plants using 1" grow cubes. I use the cubes upside down so that they seat in the planter. The cutter is for cutting a 1" square hole in styrofoam boards. Is it best to go from both sides as otherwise it will leave a jagged hole. Just pound the cutter through using a hammer. The 1" insert fits in the hole and produces a clean seat to place the grow cube into. There is also a 2" insert in case you have boards that already have a 2" hole cut in them (2" net cups are a comm