set two heavy posts, the distance you want apart, (maybe chain cross the top of the posts)
take a curved some thing, ( a few inches short of the width of the posts, and hook a chain on the curved thing, and pull the curved thing through the posts with the panel between the posts and the curved thing,
since there are long wires on one side and the short wires on the other, and the long against the posts, and the curved against the curved, thing.
the some thing could be an (old cable spool with some 2x4 nailed on the out side curve, to put even pressure on the inside of the panel).