For my 1510 TST, I used the sewing line as the LE. That kite is still in service being used by a friend, who loves it.
Just keep in mind the TST is not run all the way to the TE. Also, you can make the "tuck" narrower than the 60mm widest point (say, 50mm or maybe 45mm). You don't have to use 60mm. You can also use spintape or duct tape to "tape" the tuck in, before sewing it, and launching the kite and riding with it for a day or even a couple months, to see if you like it first.
For the shoulder wedge, you have to unpick the TE stitching. I don't have the diagrams anymore, but you can contact bob at LE kites:
Go to 1510 ARC Power Steering, about 2/3 down the page....diagrams are there.