This is a photo of one of the prototypes during testing, and shows the correct way to transition into and out of the coupler using semi-rigid RG402 coax. RG401 coax (.250 semi-rigid) should be used at the output port for combined output levels above 150w, as RG402 will run too hot.
When soldering the coax to the fasteners, place the fastener on a paper towel or cotton cloth and solder the coax in place (attempting to attach the coax after mounting the fastener requires excessive heat, and is not easily done).
Solder the center conductors to the coupler traces only after the coax has been mounted and formed into your setup, as movement of the center conductor after soldering could cause the traces to lift.
Note the use of the 150w chip termination mounted at the 'dump' port of the coupler, spaced at the correct height to mate with the port (.065).
Use of the conformable type of RG402 (like Belden 1673) is not recommended, as testing of this coax showed a return loss of only 20db at 13cm, and degraded the coupler performance a little.
The coax fasteners and termination are secured with 4-40 screws, and the coupler itself with 2-56 screws (4-40 can be used if the screw heads are small enough).
The second photo shows part of the test setup used during prototyping.