Yes, I love my J hook liner, however, had I not gone against what the instructions said, I'd have a really wrinkled bottom right now, having dipped the center really helped take up some of that slack.
As for coping strips, Dennis, I think every manufacturer is somewhat different and it all depends on your pool type since I do not have any separate coping strips....well, I better explain my setup in more detail...
My J hook overlap has an upside down J welded onto the top of the liner, this J is probably 3-4 times as thick as the rest of the liner, it just hooks over the top of the wall, there's nothing separate that clips this down, likely because I have a Vogue blow molded resin pool, and the top rail is molded with a channel that caps the top of the wall, so I would think this channel is what clips the liner - even though the fit is quite loose - I can feed a thin rope or webbing through there, but because the J is so thick, it won't slip out because the crimp (bend) in the J will not flaten enough to slip through.