One problem is that Double-X comes on a core, not a camera spool. So once you remove it from the bag and untape the end, it wants to jump off the core into a big pile of tangled curls of film, like in a cartoon! The "correct" way to handle it is with a split reel, that allows you to lay it down flat on one half of the reel, then screw the other half on, then you're all set to pull film off of it. (You can also find these on ebay - make sure to get one for 35mm, not 16mm!). And the "correct": way to pull film off of it is with a pair of rewinds and another core or spool. But I've seen people here mention simply laying the original film on core down sideways on a smooth surface, with some sort of post sticking up for the core to spin on, then just pulling it off that way. Either hand winding it onto another bulk spool, or even one 35mm 36 exposure roll at a time.

Duncan