I bent the rear channel 90 degrees for both bends and need to overbend one. The easiest way I know how is to put it in a box to hold the 106mm dimension and beat the flanges into place using a template for the angle.
Using 1/4" x 3" x 4' Poplar strips strike a chalk line the full length of the table. Screw the ends of the 4' section on the line then adjust the middle to the line and screw it down, add two more screws between the three you have for a total of five screws per strip.. Do this for three strips to establish a 12' long straight line on your table top. The picture shows the left strip attached first. The right strips are offset using 106mm spacing.