I’ve never considered dry hopping at a precise SG, I generally wait for the blow off to stop bubbling, give it a day or two and take a reading, give it another day or two and confirm it has hit FG with an identical reading, try and drop to 14c (the temperature Brewdog apparently dry hop at) throw the pellets in and then rack to BBT 3 days later.
If you’re bottling I suspect clarity shouldn’t be an issue, when you serve there should have been enough time for the yeast to drop down to the bottom of the bottle and stay there. If it is very murky in FV though you could end up with a lot of yeast in the bottle, more time in the FV should help and I cant see chilling the FV doing any harm!
My concern with chilling the FV to ~0C is because of my blow off arrangement. It has the potential to draw in a litre of StarSan into the beer. I would be interested to know if anyone has worked out the volume change in a FV being chilled. If you have an airlock and it’s not overfilled it ’shouldn’t‘ draw in a significant amount of sanitiser (some people use vodka just in case) and the amount of air drawn in ‘may not’ be an issue, but I don’t like chancing it!
Don’t worry about leaving the beer on the yeast too long, IMO you shouldn’t get any off flavours fro this for at least a month or two, if not longer. You can, however, get ‘grassy’ off flavours by leaving it on dry hops for more than a week.