Hi Brian, I've attached an updated version of your model here (BrianBoolean.zip) that can now be booleaned.

The way I formed the cutters was to build these sections which were boolean unioned together:



Then I removed the flat parts to open up a hole:



Then used Construct / Blend to place a smooth blend in between the edges that were now open, to get this result:



Now that has no self-overlapping parts and can be used in a boolean.

Hope this helps,

- Michael