Double Spinn Sheets
Essentially, double sheets & guys get used because with such a big boat, pole and spinnaker, you don''t want anything to get out of control and kill someone.
Using lazy guys and sheets enables you to do an end-for-end or a dip pole gybe, as conditions and crew skills warrant.
To dip-pole gybe, the lazy guy is eased so the bowman can slip it into the pole jaws on the new side, when its time. The pole (and guy) are eased forward and the jaw disengaged from the old guy. (Here is where the argument comes about rigging the pole jaws up (so that opening them releases the pole from the guy when you pull down on it) or jaws down, because you want the strength of the cast part of the fitting at the top, where the most strain is; you open the jaw and lift the pole off so it doesn''t just drop and bean somebody. Most boats I''ve sailed on go with the jaws down.) While the guy and pole are being eased forward so the bowman can grab the end of the pole, the new sheet can be tightened a touch to help keep the chute full without precluding the pole''s going forward. The bowman grabs the end of the pole, in any case, while another crew lowers the topping lift to the pre-marked point that allows the pole to pass beneath the forestay. The bowman slaps the new guy into the jaws, calls "made" or words to that effect so the trimmer knows he can haul on the new guy and new sheet, and there you are. A smart bowman then adjusts the lazy guy and sheet to positions so they''re ready to gybe back again. An end-for-end gybe works similarly, except for not having to coordinate the timing of the topping lift, and not calling "made" until the pole is re-attached to the mast fitting. Hope this helps. There are a bunch of books that outline this in better detail or with differing options. Borders or Barnes & Noble would be good sources.