First of all, welcome, my KY brother, to the site. Lots and lots of great people here willing to help.
I can't help you with the brace heights on those bows, but I can tell ya that you need to be weighing your arrow stuff in grains, not grams, for better comparison. Or, be able to convert grams to grains. I would have thought that the 2016 with 125 gr. points would be heavier than 380 gr. :confused: Yes, just adding weight to the tip will change arrow spine. Also, changing the length of the arrow will change the spine. Maybe try the method that was mentioned about putting rope inside the arrow to add more weight.