So on the El Camino frame you mentioned, why use that instead of boxing a HT frame? If you are considering the ABC minitubs, you'll be sectioning the rear frame rails anyway. Plus, the El Camino frame is longer behind the rear axle, so it would need to be shortened anyway. Just my thoughts.
I boxed and notched mine before Tony's kits were available. Now that the parts are available, it would be a huge time saver to use them. Could you do it cheaper? probably. But not when you figure in all the time to make templates, adjust, cut, trim, and weld them.
DSE makes some quality stuff no doubt, and it works. As you know, I have ABC front and rear stuff with Ridetech T/A's on mine. Couldn't be happier. But I have nothing but stock stuff to compare it to. One thing that is unique about his rear suspension is the use of OEM type cross-axis joints for full and smooth articulation. Plus the joints are fully sealed too, a plus for daily driven cars. I think the Ridetech suspension would be a great setup too. Too many choices
All things to consider of course.
Ok, you started the build thread, now we can hound you for updates