5/8" drillbit alignment tool

I need to run a PVC pipe through my wall. The hole saw drill-bit and saw are fixed in place and the starter bit is not long enough to cut through both dry-wall panels in the wall at the same time. Doing this, even measured from the floor and a common wall would likely be too inaccurate for the PVC pipe to be level at the end of the hole-sawing. Power-tools are not my friend. So I want to use a separate and long drill bit to make a hole through both dry-wall panels (on both sides of the wall) to start the saw on each side. I want the starter hole to be vertically level and precisely perpendicular to the wall horizontally.

This is what I came up with. I printed it with PETG. It worked!