When running heavy things up the rig, that might swing around potentially damaging the rig, or tossing someone trying to control it off the boat.., they use what they call a "tracer line". Maybe it's common, but I have sailed a lot, and raced a lot on many different boats, some of them pretty big, and I hadn't seen it before, but it works brilliantly.
The tracer line can be a dedicated line.., but I imagine you could also use a spare halyard. The tracer line rus down from the top of the rig. It gets secured to a padeye somewhere on the foredeck, and the other end gets tensioned with a winch. Then the heavy thing that needs to go up has something like a carabiner on it, which is put on the tensioned tracer line so it can slide up. Typically this will be the metal fitting at the top of a furled headsail.., say a Code 0, or an A3. On big boats, these furled headsails are really heavy, and can swing quite a bit on the way up before they are tensioned, especially in big waves. But, sliding up on the tensioned tracer line, they are completely in control. Once it is up, the tracer line is eased and attached at the botom of the mast. When the sail comes down, the tracer line is re-positioned, and the furled sail comes down the tracer in complete control
I didn't see it being done with a snuffer.., but i imagine it could be.
The superyacht guys are interesting.., they deal every day with boats that are trying to kill them, and have developed specialized techniques for doing things that we might do more casually on smaller yachts.
Even on yachts in the 65-75ft range, and I have sailed quite a lot on boats in this size range, you can generally get away with not doing things perfectly.
But when the loads on the lines get to be many times what they are on say a 70ft cruising yacht, you can not afford to screw up; people will get hurt, or worse.
