I originally went with the WCB adapter but was not happy how it forced my fittings to come in contact with the frame. Basically, to thread anything onto the lines, I would have to loosen / remove the mounting bolts.
The better option, for me, was to redrill the frame and make a small notch in the crossmember to account for the 3/8" plate on the frame side plus a nut and washer. The plate covers all 3 bolts so I don't see anything pulling through my frame. Some report they experience pancaking of the frame, but my original spacers are intact and I will monitor the nuts over time to make sure I am not in need of tightening.