All righty then. Finished welding up both arms. I also figured now would be a good time to weigh a stock arm vs the modified, looks like it gained a lb and a half (weighed on bathroom scale, so that's approximate).
Also I forgot to mention previously that the original setup with the tube just the same length as the frame rails on the arm doesn't work, because the rear actually adapter has to hang back behind the frame rail in order to line up where the originals did. I could have lined the tubes up at the front end, but by the time I realized all of this I had already cut them and welded the adapters in, so it was just easier to leave that extra 1/2" of tubing on the end.
Still got to get that inner heims joint adapter done. I think I'm going to try and find a local machinist again and see if I can't get that going.