Don't know if these are covered elsewhere but two things I did with my SE: 1. Before you sheet the root end of the wings, the hole where the J-hook goes toward the leading edge of the root rib. Place a small square of scrap ply and a 4-40 blind nut for the J-hook to screw into. Be sure to securely glue, CA or epoxy the blind nut. Otherwise all you have to hold the J-hook is ply threads.
2. Instead of using rubber band to tie the J-hooks together inside, go to the hardware store and get a stiff spring about 3/8 to7/16 diameter and made of about #18 size wire and one that is about 1 1/2 to 1 3/4 in long and use this to stretch between the J-hooks. Has about the same force ans the recommended rubber band but much more secure.

Be sure to start out with minimal throws on the control surfaces. The plane is a nice flier but squirrelly at first Increase the throws as you get used to it.

The plane goes together very nicely, everything fits well and you really don't need a jig. Just make sure the ribs are square. Best kit I have ever put together in 30 years of building and flying.

Cheers..