looking like something good now
, its great when you start to see the design concept form into a real item.
The terms "light" & "copper" used together is kind of an oxymoron, but I always try to now approach my builds from the make it as light as I possibly can direction. It isn't easy unless you are willing to use Perspex / acrylic etc.
Only other thing I can see, (and don't jump on me if you have it hand), is you'd ideally want something on the square section that will touch the pcb opposite the core, mica shim possibly