I'll be changing the pistons on my 360/426 stroker

You can get 4 to 5 grams out of a piston without a ton of work. And you can get some out of the small end of the rod. If you can take the weight all out of the new piston + the small end of the rod, then you are done. No need to touch the big end of the rod or the crank.

If the piston is heavier, and you do not take enough weight out of the piston and small end of the rod, then you can take it out out the big end of the rod and get to the previous bobweight. Then you still don't need to touch the crank.

So the change in piston + pin weight is important and worth the effort to find out. You can save a lot of work if you plan it right. (And we are assuming that the same ring pack is used, so that there is no weight difference there.)