I'm building yet another design. A compact 4 site under-current system, for a 4x4 tent.
For the 2" DIY conduit bulkheads, the size hole saw needed is 2-3/8". The nicer heavy duty kind (lennox, etc). It actually is perfect without sanding if you don't use the flimsier cheap hole saws that are thinner metal, and the teeth don't stick out as much...
First, drill a small pilot hole, on your mark, and with a smaller bit.
Then drill down into it evenly with the 2-3/8" hole saw in reverse. Get the RPMs up and just keep pushing till it basically melts through. Practice a few times on a scrap bucket if needed first. You kinda get a feel for it after a few holes. Before it cools off you can peel the top outside burrs off the hole with your finger nails. I use a box knife razor blade to trim the inside of the hole, keeping it pushed flat against the rim at a slight angle as I spin it around. Kinda of tricky to not cut in, and just skim it instead.Or your finger. I recommend a deburring tool if possible..
Then, the male terminal fitting threads slide right in. Keep the o-ring or gasket to the outside.
This is using Lowes 5 gallon "Commander" brand square buckets for the sites.