I measured my bridle offsets last night for a friend who also has a J7 15m, posting here to keep a record of what works well...at these settings the kite behaves in a way that I think requires somewhere between "advanced amateur" or "early intermediate" level of kite skills. Some slight tip tuck at times, but that's a good thing for responsiveness and turning speed...very manageable, fast, and stable.
Measurement method: attached flying line connectors to a fixed point, laid out kite, bridle, and speed system, pulled everything mostly snug and used light tension to make measurements between bridle rows. I measured from the bottom of the knot where the knot attaches to the connector on the canopy (on a Flysurfer this is where the LCL would attach, but Elf doesn't have LCLs
First power rib (N1), measuring relative to the A row: B -48, C +8, Z +381
11th power rib (N11): B -51, C -52, Z +267
Those offsets seem nutty to me, and to be honest they don't match the numbers I was given by a friend who got the numbers from Elf, but my kite flies fine, no real complaints, so I won't mess with what works!
Upper pulley line looks like it's about 70cm, lower pulley line looks like it's about 134cm, did not measure the Diablo line...