At a guess about 25% will go stick here but less in Europe. In Germany there is little interest in stick these days. Much more a North America issue though I have idea why. I kept my old RS which does not even have stability control for when I want to drive a stick. Not going for any gen 2 cars but would not wanting to be holding a 991R at present. New car had manual and wil handily outperform it.
My next 911 will be a 992RS I expect and will keep whtat I have. There will always be some space for manuals though interestingly the more exotic marques like McLaren and Ferrari as well as the super exotics have abandoned them