I am not sure I follow. If you go down the key route, you need to account for half of the key height in the bore. I've had keys done in quite thin boss widths in relation to the bore without breaking. I'll see if I can get a photo of the key.
Yeah, dyslexia's a bit of a you know what. I guess what I'm trying to say is that in that image, and with what the listing says is that the boss diameter being 14mm, and the shaft being 12mm, I'm honestly not sure the thin boss width'd be a bit too thin. Or am I just worrying for no good reason?