ive been doing that repair i will post pics in the morning , its complicated and careful work . also the repro cross channel needs a couple of extra reworks to it to make it like the original, including fabbing the ends to connect to the door post bottoms and redrilling for holes put in at the wrong places and adding ones that were not put in at all but are on the original . plus of course there is the patch panels that also need to be installed for the cab back and corners . im taking it slow and getting all the pieces cut and fit before welding and than there is the interior rust that will be revealed when you get that swiss cheese out of the way. lovely work.. just take your time and make it as right as your skills can give it . pics on thursday day.
edit
sorry for the delay much juggling in the shop these days. here are the pics and by way of explanation note the differences in the end of the repro piece and what was added to it also the repro was not as wide as needed so i had to open the corner so it would reach the post . also note that if i did not add the end connecter the corner patch would have no where to be tack welded on, the cab back and corners all tack weld to the bottom edge of the cross member, the repro also need hole to be redrilled for correct alignment as well as for adding holes that were not put in at all .
hope this helps