Unfortunately you can no longer get the dark gray ( the can in the middle) spray paint.
They changed the color and the formula.
I think that Tamiya German gray would be a good replacement.
The before and after pics do not quite catch the true color of the redo.
The picture with the plate , spike...
Not bad for your first one.
You can touch up the plate with black wash that you can buy at a hobby shop to make it blend better.
Chances of finding a matching plate are slim to none.
I made a post on doing this in the restoration post.
I will try to bump it up for you.
The loops on the plate almost always were attached to the helmet with leather wedges.
These wedges actually helped pad the loops with addition of the liner against the wearer's forehead.
These metal wire pins would actually press against the wearer's forehead.
So without a doubt they are post war.
Back in the day I had the same regiment plate that was missing the orb and claw.
I had a matching doner plate that I took to a jeweler and he gold soldered the orb and claw to the Gorde plate.
It turned out great !
Would it be easier to use a rear visor off of a fireman's helmet?
You could run a wooden stick in the brass grove to make it accept the thicker leather.
And/or skive the edge to accept the brass.
They are usually larger and could be made to fit.
I made a shell out of thin pasteboard to fill out a white shako cover.
I Will try to post pics later today.
The mortar board should be easy enough to make along with the neck.
I used a plastic salad bowl to make a form to stretch liners out to install in my felts .
This would work as well to...