Hi Robert, one thing is the larger pieces are open surfaces, not closed solids and so that will make it more difficult to boolean them together.

Then the other thing is to avoid gaps you should probably model it initially as a straight piece and get that all booleaned together, then remap it from a straight piece into its bent form using the Transform > Deform > Flow command rather than using array along curve.

For Transform > Deform > Flow you would create a straight line down the center as the base curve and your bent curve as the target curve, see here for some examples:
https://moi3d.com/4.0/docs/moi_command_reference8.htm#flow

Flow will make the geometry stretch and compress so you won't end up with gaps between pieces like making undeformed exact copies will.

- Michael