Ref the stock mirror stalk remains, I spoke to the factory asking them to use Allen bolts or similar in order to be able to remove the remains of the standard mirror stalks, which, of course, look pretty hideous otherwise.
The show bikes had stainless button head Allen bolts fitted in this application, which looked perfectly ok.
However, it is, and I quote: “Too difficult and expensive” for the factory PDI dept to do this...
So, I ordered a couple of left and right hand thread socket head stainless Allen bolts, off of eBay for peanuts.
So, it seems, a crisis has been averted.