Nice work Majik!

I see why we are both interested in creating grouped "Sub-assemblies" that move around and stay together as a whole - you have eight of them!

Yeah - MoI works well for me because the Booleans are a kind of a "machine shop" metaphor for me.

Boolean subtract is like a milling machine where I start with a big block of metal and cut away material.

Boolean add is like fusing pieces together with a TIG welder, but with clean joints :)

Revolve is like using my lathe.

And finally, I like to work with solid chunks of metal, rarely with sheet metal (surfaces) :)

Anyway, that's how I think of it.

Ed