> So to clean those up I used Edit > Separate on your model to break it into individual surfaces, then picked 2 of those fragments at a time and then did boolean union on the 2 fragments to get a result without any interior edges.

Yes, this is a good way to rebuild objects. It works fine :)
Thanks for the description in your links.

The additional commands are great! At this point i didn't know the other commands, but the "rebuild" function for curves.
I now understand much more about how to create "clean" surfaces in Moi.
Your support helps me a lot!

Thank you!

Jörg