Also do you possibly have a version of this file saved off _before_ trying to do any of the boolean unions rather than only in the kind of halfway combined state ?

If you can post the pre-boolean file that would be an easier starting point for me to try and help you get it combined.

It may involved doing some trimming of the legs rather that booleans. Booleans are kind of like a "batch mode" version of Trim where it does something like a Trim + automatic figuring out which pieces to discard based on which volume they are in + join. With trim it just basically intersects things and lets you pick which pieces to keep or discard manually, Trim has less stuff automatically happening and can be effective in cases where the booleans are getting confused.

- Michael