Well, I'm just along for the ride here since I am building a stocker lowered with a few moderns, so I have no advice for you here
But I wanted to say it's looking good man. I have been watching SCOTI build over in the early 60's threads and he is really building something awesome over there, very custom. And you might hit him up if he isn't already following your build for answers.
I also have a question, where did you find the HD trailing arms? What advantages do they give you besides durability? And last, I need to check out this airbag helper system, I plan to use my truck and that might be something I need. Who sells these kits at a good price but good quality?
Keep it up man, looking great!