This platter as you see it, weighs in at about 3.5Kg. The Copper Bonded Solid Alluminium Platter comes in at about 6Kg both depending on the thickness.
The stock platter weighs in at about 1.5Kg
So your new platter weighs roughly half of that of the aluminium platter... Interesting.

As an aside, note how successfully the black platter compliments the well at the base of the stock tonearm (the same would also apply if an ebony armboard were fitted):





I know you're not as focussed on aesthetics, as you are on engineering your designs, but trust me, these things matter!

Any idea yet what you're going to call your new platter? What exactly is the material that it's made from called?

Also I am now machining a 2mm outer skirt under the platter edge, so that anyone who decides to fit the Bearing base Plate at a later date, can do so without upsetting the aesthetics.
Good idea. I'd also incorporate a label recess, as standard

Marco.