360 Magnum mated to 904

I called B&M to ask about mating my 360 Magnum to a 904. The tech guy told me that the flex plates for 360 magnums were matched to each particular engine by either weights OR by holes drilled to balance it.He also told me that the earlier magnum engines had on hole offset in the flexplate and all that i had to do to mate it to a square pattern converter was to elongate the hole. He told me that to run an aftermarket converter without weights with an aftermarket balancer that I needed the flexplate that came with the engine, an aftermarket balancer specifically for the 360 Magnum and an UNweighted converter. I have heard of other combinations that worked and was wondering if anyone had done this particular setup as I already have all the parts and don't want to have to spend more money???