In pictures my core thread comes from the spool. The re-loaded shuttle is yellow in pictures. I also used an auxiliary shuttle (named OLD in pics, blue one) to better manage the short tail of the old thread.
This method is very similar to that one used for rings, that you can find here:
"Planning for the End..." http://www.bellaonline.com/articles/art29954.asp
(Matthew Takeda's method - at the end of that page)
More on the Adventure of the necklace still coming!