FYI: I went through the same issues for balancing. Earlier 5.9 were externally balanced later internally.
Which ever balancer you find that works verify that TDC and your timing mark match. Mine was off 6 degrees. Drove me nuts until verified.
The 360 were all externally balanced. The 360 magnum has a lighter rotating weight than the LA360. I am still unsure about the one i posted
Because on the website it shows the balancer working on a 89 360. I am going to call the company Monday and see what they say