possible 360 build

Might have already asked but haven't seen an answer if so sorry for the repeat
I mainly want to use the flat tops in the magnum block. What's it take to get a crank balanced neutral instead of external?
I can go with either the LA or a magnum 360 crank. And do I use the magnum or the LA rods? Or would it matter?

I Know that you can use LA pistons or crank or rods, in a 318, either magnum based or LA based.
The casting number of the 318 crank is the same from 1968 and up. LA and magnum. But from what I understand the amount of Imbalance is different from the magnum 360 to an LA 360.
I have this conglomeration of 360 parts collecting dust that I'd like to put to good use instead of continuing to collect dust, but I like the idea of neutral balance in case it gets stabbed in in place of a 318 or even a 6 cylinder.