Finished up the flasks.
This was the set-up for drilling the holes. Instead of marking all of the flasks for the hole locations, I put marks on the table that I would line up the edge of the flask. Once the marks were made, it went fairly quickly drilling all of the holes.
Here is the finished product. I used a belt sander to flatten out the mating surfaces. The alignment pins are bolts with the heads cut off and I put an adjustable alignment bar on one of the pins which is made from a pieces of aluminum flat stock with a V shape cut into it. I worked out really well. I can't wait to try it out.